Alternator question, battery is discharging quickly.

[FC Zach]

For a while until this Monday, I have been dealing with some mystery drain to my battery. I found it by accident while detailing the engine bay where I heard a faint electrical whine that seemed to come from the alternator which stopped after removing the battery lead.

Before finding this issue, I'd have to keep a trickle charger connected to the battery or else it would completely drain within a couple weeks. It was attached when I found this problem. I left the lead off the alternator and disconnected the charger and left alone for a few days.

After giving it a few days with the charger and alternator disconnected, I reattached the charger to see if it would attempt charging the battery but it didn't. It was fully charged so I can confidently say it was the alternator.

Details:
-'87 RX7
-3rd Gen Alternator
-The 2 pin connection on the alternator is vacant
-Battery is good, tested. Tried another in case.

My questions:
-Does the two pin connector need to be connected to the alternator?
-If it's not a bad alternator (going to test it soon), any recommendations on what to check next?

[djmtsu]

One of the pins on the alternator needs to be connected.

Noob.

[FC Zach]

It used to be connected. . When researching about it years ago I was under the impression that it was a redundant connection. So. . some time ago, about the time I converted it to EFI, I removed that connector to clean things up.

Since it's been a while since I've done this, I do not remember where that wire goes. Is it switched or constant 12v?

[FC Zach]

With that being said and before it's mentioned. . I never made the connection of the two because I thought the drain was related to the Haltec wiring and not this little single wire connection.

[djmtsu]

I believe switched. The main power wire is of course constant.

[FC Zach]

Sweet. . but what change would it have in my case if that connection is switched 12v?

[FC Zach]

When I connect the bottom pin to the battery lead on the alternator, the whine goes away.

[TitaniumTT]

One of the pins needs to be connected to the battery, or a constant 12v+ source. The other pin pulls current through the idiot light. If both of these aren't connected, it will drain.

If you only have ONE wire run to the Alternator, you can use a resistor to mimic the difference in current at the alternator.

[FC Zach]

Could I simply do this, connect here?

https://c1.staticflickr.com/3/2909/32226303104_126e1e0db9_c.jpg

[TitaniumTT]

Sounds like the bottom pin goes to the battery, the top pin goes through the idiot light.... oh, that pin needs to be keyed as well

[FC Zach]

I've never had the top wire (the empty spot in the connector) connected to anything. Is that recommended?

[TitaniumTT]

Could I simply do this, connect here?]

You could, and you could use a resistor to connect to the top pin, however the top pin needs to be keyed or you'll get the same drain

[TitaniumTT]

I've never had the top wire (the empty spot in the connector) connected to anything. Is that recommended?

It's necessary to keep the alt from draining the battery, unless you do a complete battery disco, which I usually do anyway because Rotary.

[FC Zach]

Ok cool, thanks guys!

One problem though. . I don't remember but does this connector have the "idiot light" wire you speak of?

[TitaniumTT]

Yes, one wire is straight to the battery, the other pulls through the idiot light.

[FC Zach]

Oops, forgot to attach pic. . Can the to wire be connected to this, do you know off the top of your head?

http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=17090&d=1487864599

[FC Zach]

Just checked the manual and the my OE plug would have been a small T shaped connector. Mine is not there. oh well, I'll have to figure something out.

[TitaniumTT]

That looks like the CAS wiring and if that's still there, you might be able to use those wires to power the ALT, with come retasking of course

S4's use the T-shaped connector, S5+ use the style that you're using.

What happened to the T connector?

[FC Zach]

When I went carb, I removed the harness.

[djmtsu]

When I went carb, I removed the harness.

Yes, however that plug is on the driver side POWER harness, not the ECU harness. The CAS is also on the power harness, which you clearly still have.

It's there somewhere....

[TitaniumTT]

Ah. Ok, so heres what you need to do.....

Buy Scotch
Buy plane ticket
??????
Profit

Butt seriously, depending on how much of the harness you cut back or removes, and I think I know which harness you pulled out ... Giggitty ... you need to go back to the FE-03 connector, between the "Front" & "Engine" harness and find the B/W & W/B wires and run them up to the alternator and plug them in. That will do it.

If the FE-03 connector isn't around anymore, you can get them on the FEM-01 plug and route them up to the Alternator. That plug is or course located around the stock ECU.

Now, if you've already got a nice Ludwig Harness and you don't have the provisions in that harness for the Alternator, what you can do is use the vacant CAS wiring that you showed the pic of. Those will be in the Front Harness and routed over to where the ECU lives. From there it's a matter of jumping the wires from the FEW-01 plug to the CAS wires (R,W,L,G) and then making the connection to the Alt.

Any of those approaches will properly control the Alt and prevent battery drain. But the key is, regardless of what the internet says, or the GM crowd, the alt NEEDS both wires to work properly and not kill the battery either by slow discharging death, or 16V overcharging death

[FC Zach]

Where I'm at so far.

https://c1.staticflickr.com/4/3860/32227925584_975ac51923_c.jpg

Going to connect the top to a switched 12v source but need a resistor?

[FC Zach]

Yes, however that plug is on the driver side POWER harness, not the ECU harness. The CAS is also on the power harness, which you clearly still have.

It's there somewhere....

It's not there.

[TitaniumTT]

Do you have my number?
Are you off today doing this shit now?

[FC Zach]

I'm a night shifter, been at this for a while now.

[FC Zach]

No number.

[djmtsu]

I have sweet Brian's number....

[FC Zach]

He's got you blocked and has a restraining order against you :)

[TitaniumTT]

^ :smilielol5:
DJ, you want haz play matchmaker?

[TitaniumTT]

Hey Zac, remember what I said about the 7club being all fuuucocked? Well..... yeah... Check this out,,, ignore 7Dust, he was handed the answer 3 times I counted, he's a fucking stubborn idiot... I dunno what it does, so I'm gonna leave it unhooked. I don't care about idiot lights, so I;m going to leave it unhooked. There's the problem

Satch & RockLobster know what's up. It's exactly what I found out and now mine works just fine ;)

http://www.rx7club.com/2nd-generation-specific-1986-1992-17/alternator-wiring-scratch-1048705/

I wired my race car (s5 alt) without any of the stock harness, getting the alternator to work properly was the biggest pain. Until I basically learned what all the wires do. You need all 3 wires connected. If you are not using the stock harness you need to create these circuits or the alternator will either not work or kill itself.

B terminal is the obvious part. That's the charge wire. It...um...charges the battery...min 4 gauge IMO.

S terminal needs direct battery signal, can't go through a relay or any switch. It can go through a fuse. This is the "sense" wire. It tells the internal alternator voltage regulator what the battery voltage is and thus how much "charge" to put into the system. The closer you connect this to the battery the better your alternator will work. If you just jumper it to the charge post it really wont fluctuate voltage output to adapt to battery state and load conditions.

And last but not least the one that had me thinking like you. The L terminal which is where the excite wire connects. Yes it does power the idiot light. It does this because current flows if there is a substantial difference between the system or batt voltage and the alternator charge voltage. This terminal/wire must be connected because it is in effect what "turns on" the alternator. BUT and this is a big but. YOU CANNOT JUST CONNECT IT TO A HOT WIRE OR THE BATTERY. It must have resistance or you will destroy the alternator voltage regulator and the alternator will need to be rebuilt because it will not regulate voltage, the voltage will just rise with RPM up to 16-17 volts. I don't have to tell you that is bad. SO, the factory dash has two parallel sources of internal resistance. One is a light, the other is a standard resistor. You CAN NOT skip the resistor because if you just use a light and the bulb burns out, guess what, your alternator shuts off. So, you have to wire this terminal back to +12v (again no relays upstream for this one too) but you must also put a roughly 120-150 ohm resistor on this wire. Up to you if you want a charge light in parallel. It appears in some cases (3rd gen rx-7 and other cars) the factory dashes just use multiple idiot lights as the redundant sources of resistance for this. So if one bulb burns out the alternator does not just quit working. If you do put a charge light in parallel you need to put a diode in also or the light will be on all the time. The diode should only allow current flow TO the alternator. It needs to BLOCK current flow back from the L terminal.

I think in your case your alternator may be damaged or isnt charging because it isnt turned on. But your assumption that the alternator "stays on" when the engine is not running is incorrect. This isn't actually possible. Without the little wheel spinning on the front of the alt it's basically a paper weight, it cant be on without being driven. But, if you damaged the voltage regulator it may create a bleed. If i recall correctly when i blew one trying different things to get it to work properly (read just put unresisted +12v to the excite terminal) it self excited after that and would not regulate voltage at all.

Some reading for you: http://bob_skelly.home.comcast.net/~...ternator1.html

This basically explains all this, probably more eloquently than i did.

The Bob Skelly link I BELIEVE is the one I was telling you about

[FC Zach]

Thanks Brian! That is a good explanation for me especially since I will most likely be wiring this from scratch, I'll need something for reference material. After I got off the phone with you I just couldn't go to sleep without inspecting more. Even though we were positive it doesn't contain these wires I checked an extra engine harness (passenger side) that I had laying around and it was loaded with 'T' shaped connectors so I just threw that back in the box. . . I looked for possible remains my OE two pin alternator connector by peeling back the loom on the drive side harness, still nothing. It wasn't there but what I did find was that my alternator was warm (this was after leaving that connection I made on the previous page connected for what, a couple hours?). . Looking into that, I found that I had the 'L' terminal (for dash) connected straight to battery, definitely not right.

http://www.rx7club.com/attachments/3rd-generation-specific-1993-2002-16/543953d1412299984-fd-alternator-wiring-altinstall.jpg

[FC Zach]

The Bob Skelly link I BELIEVE is the one I was telling you about

That link is dead

[RETed]

1) The 12VDC reference wire (which you call a "pin") needs to be connected to +12VDC constant, direct to the battery.
This is applicable to the FD and Kouki FC alternator circuits; prior to that, the Zenki FC alternators were only wired to switched +12VDC.
This tells the alternator what the status of your battery is.
Try not to connect it to the +12V post off the alternator, cause it'll be higher than the battery + post, and there's chance that you get back EMI from the alternator operation - this is why you don't see the OEM's wire it to there, even though it's a short shot.

2) The other pin is for the idiot light.
Like others who have already said, it's not necessary to connect this to anything.
This just completes a circuit (to ground?) so your idiots lights light up when the alternator fails.

As for your problem...
I had the old silverrotor FD alternator, and it always had a major drain with the engine off.
I bandaided the situation by resetting my circuit breaker anytime I left the car off overnight.
I traced the problem to the alternator sense field not dropping even after turning the ignition key off; for some reason when I dropped the +12V reference, this would drop the field and killed the excess current draw immediately.
I just chalked it up to a crap rebuild (these things were rebuilt by silverrotor by some shop).

Once I replaced with another unit, I NEVER had that problem anymore.

So it's quite possible you're in a similar situation.

It could be possible that you have a shorted diode in the rectifier, which would cause the alternator to keep draining voltage with the engine off too.
I've fought this problem with my MX83 alternator, because I think the 15VDC+ levels my battery charger was giving it when I had to jump it.
In this situation, every time you reconnected the alternator, the current draw would always be too high.

It's very easy to troubleshoot these things, as you need someone to measure current - most DMM's do this.


-Ted

[FC Zach]

1) The 12VDC reference wire (which you call a "pin") needs to be connected to +12VDC constant, direct to the battery.
This is applicable to the FD and Kouki FC alternator circuits; prior to that, the Zenki FC alternators were only wired to switched +12VDC.
This tells the alternator what the status of your battery is.
Try not to connect it to the +12V post off the alternator, cause it'll be higher than the battery + post, and there's chance that you get back EMI from the alternator operation - this is why you don't see the OEM's wire it to there, even though it's a short shot.

Pin/Terminal. . . whatever, you know what was being referenced. :001_005: But yeah, I am redoing the wiring now.

2) The other pin is for the idiot light.
Like others who have already said, it's not necessary to connect this to anything.
This just completes a circuit (to ground?) so your idiots lights light up when the alternator fails.

That's what I thought too but is contradicting to what others have said. Some say it has to be connected and others say not necessary. .

[FC Zach]

As for your problem...
I traced the problem to the alternator sense field not dropping even after turning the ignition key off; for some reason when I dropped the +12V reference, this would drop the field and killed the excess current draw immediately.
I just chalked it up to a crap rebuild (these things were rebuilt by silverrotor by some shop).

Once I replaced with another unit, I NEVER had that problem anymore.

So it's quite possible you're in a similar situation.

It could be possible that you have a shorted diode in the rectifier, which would cause the alternator to keep draining voltage with the engine off too.
I've fought this problem with my MX83 alternator, because I think the 15VDC+ levels my battery charger was giving it when I had to jump it.
In this situation, every time you reconnected the alternator, the current draw would always be too high.

It's very easy to troubleshoot these things, as you need someone to measure current - most DMM's do this.


-Ted

I'm afraid I will still have some sort of issue even after making the proper connections. . . I drove for far too long without the 12v reference wire connected. I added new leads to the connector, now to make the connections once I find the easiest/best route to take.

https://c1.staticflickr.com/3/2794/32730646210_dbfc3a393a_c.jpg

[TitaniumTT]

1) The 12VDC reference wire (which you call a "pin") needs to be connected to +12VDC constant, direct to the battery.
This is applicable to the FD and Kouki FC alternator circuits; prior to that, the Zenki FC alternators were only wired to switched +12VDC.

As odd as it is, I have close to zero experience with the S4 stuff as I never had any problems with the S4 alt because everything was virtually stock. It wasn't until I upgraded to the FD Alt that I started having issues. Much like you Ted, when I started with the FD alt, it was rebuilt by IRP and never worked right, I too blamed a shitty reman, although as it turns out, that probably wasn't the problem

Regardless, in this case with Zac, he's running an FD Alt and it needs to be connected straight to the battery, not a switched source as is already there, so that is definitely problem 1 in Zac's case

This tells the alternator what the status of your battery is.
Try not to connect it to the +12V post off the alternator, cause it'll be higher than the battery + post, and there's chance that you get back EMI from the alternator operation - this is why you don't see the OEM's wire it to there, even though it's a short shot.

The EMI I hadn't thought of, that's a valid point. In all the searching when I was having all of my issues, the general consensus as to why that singular wire is run back to the battery is because we're altering the output of the alternator based on what that sense wire is telling us. Just because it's 14.4V at the charging post, doesn't mean that it's 14.4V at the battery and that can be due to a variety of reasons.

2) The other pin is for the idiot light.
Like others who have already said, it's not necessary to connect this to anything.
This just completes a circuit (to ground?) so your idiots lights light up when the alternator fails.

This is where I disagree. This could very well be the case for the S4 alts but it is NOT the case for the S5/S6 alts. The later years NEED the idiot light pin to be hot when the key is on and the alt is spinning. If not, it will die an agonizing death.

Again, I don't have the knowledge of the S4 alts just because I NEVER had a problem with mine because stock, but when I did the Cosmo swap and the S6 alt upgrade, I had issues for about 5 years... literally... because I was only running one switched wire to the alt. The death was always the same, it would start overcharging and eventually kill itself and the battery.
Also, with only the one wire for the alternator connected to a key hot, when the ign switch is off, the Alt would kill the battery in a matter of days.
Again, much like you, Ted, I solved that problem by flipping the breaker everytime I got out of the car - NBD

As for your problem...
I had the old silverrotor FD alternator, and it always had a major drain with the engine off.
I bandaided the situation by resetting my circuit breaker anytime I left the car off overnight.
I traced the problem to the alternator sense field not dropping even after turning the ignition key off; for some reason when I dropped the +12V reference, this would drop the field and killed the excess current draw immediately.
I just chalked it up to a crap rebuild (these things were rebuilt by silverrotor by some shop).

Once I replaced with another unit, I NEVER had that problem anymore.

It sounds like it was a bad alt and it was pulling through the relay/idiot light and keeping the alt energized which would quickly kill a battery.

The "Sense" wire, the S wire, in the S5/6 is connected straight to the battery. It senses the voltage and adjusts the output of the alt to attempt to feed the battery the needed 14v. On the S4's it's called the R terminal, and that gets fed to the B/W wire which is hot when the key is in any position other than off.

Both the "L" Terminals on the surface accomplish the same thing. They illuminate the idiot light when there is a problem. However, as far as the alt is concerned they accomplish very different things and it can be seen in the wiring diagrams.

The S4 has a diode on the relay that only allows current to travel one way. When the alt goes bad, or is not charging, the W/B wire latches to ground, which energizes the coil, which closes the circuit in the relay to ground and with the other side of the idiot light connected the B/Y wire (also key hot) the light illuminates. It appears to me that the S4 alts can be run with only a single wire and run properly and as designed (meaning they won't die quickly) by leaving the idiot light wire left unhooked. Regarding the S4's, the L wire is an output, not an input as it is on the S5/6's

So it's quite possible you're in a similar situation.

It could be possible that you have a shorted diode in the rectifier, which would cause the alternator to keep draining voltage with the engine off too.
I've fought this problem with my MX83 alternator, because I think the 15VDC+ levels my battery charger was giving it when I had to jump it.
In this situation, every time you reconnected the alternator, the current draw would always be too high.

It's very easy to troubleshoot these things, as you need someone to measure current - most DMM's do this.


-Ted

The diode is most likely blown on Zac's car because it's an S6 alt.

Pin/Terminal. . . whatever, you know what was being referenced. :001_005: But yeah, I am redoing the wiring now.

That's what I thought too but is contradicting to what others have said. Some say it has to be connected and others say not necessary. .

Let me state this as fact, because I've fought these issues and anyone running an S5/6 alt on an S4 car is going to run into these problems and I can say with certainty that you need to have both wires connected and working properly for the S5/6 alts to live a decent life ... TRUST ME! :smilielol5:

I'm afraid I will still have some sort of issue even after making the proper connections. . . I drove for far too long without the 12v reference wire connected. I added new leads to the connector, now to make the connections once I find the easiest/best route to take.
c3a393a_c.jpg[/img]

Zac, right now, or rather before we started chatting, you only had one wire connected to the alt. How was that wire run and is it constant hot? ACC only? Acc and start and run? If it's a factory S4 B/W wire, that will work fine, you just need to add the resistor that we talked about. Then the S lead can run straight to your battery and it'll work fine, assuming it's not already fucocked.

[FC Zach]

Zac, right now, or rather before we started chatting, you only had one wire connected to the alt. How was that wire run and is it constant hot? ACC only? Acc and start and run? If it's a factory S4 B/W wire, that will work fine, you just need to add the resistor that we talked about. Then the S lead can run straight to your battery and it'll work fine, assuming it's not already fucocked.

Up until recently I had only the main battery charge cable ran but in the past, I had a lead running to a switched 12v source I found on the driver side strut tower in a vacant connector attached to the fuse box bracket. Where I had the opposite end of that lead going? ? ? I don't remember but I think I had it on the "L Terminal" so if that's the case, I've never had a reference from the battery connected to the "S Terminal".

What I'd like to do is find the old alternator wires or the connector/harness they would have come from and wire my leads there. . . wherever that is.

[TitaniumTT]

Gotcha, If you had a switched 12v source connected to the L terminal, chances are it's probably cooked, sorry.

Here's the problem, you're going to have to modify the wiring significantly if you're going to use the chassis wiring (S4) with the S6 alternator and have the idiot light work correctly

Ok, so before you go digging into the harness looking for the mystery wires here's what I would do
Use that existing 12v key wire that you originally had running to the L terminal. Put a small resistor on that wire (I can tell you what I am using tomorrow night) and connect that to the L wire on the S6 Alternator. Yes I realize that this sounds alot like what I just said probably cooked your alt, here's the difference, look at the S6 charging diagram. You'll see the L wire runs to the alt via the ignition switch (so it only sees power when the key is on) through the idiot light in the dash (resistance) and through a diode (one way check valve). So by using that wire on the shock tower (which I'm assuming is B/W or B/Y), you can add a resistor to mimic the resistance of the 1.4W dash bulbs and that solves that problem. Now the S6 will think that your B/W or B/Y wire is being fed through a lamp circuit like it should be.

The S wire on your alt can be temporarily hooked up to the alt charging post or brought back to the battery, either will work fine for testing purposes.

There is a big difference in the way the S4 works from the S5/6. The two main differences are.

The S4 uses the R terminal to turn itself on, and to sense the voltage. The S5/6 uses the L terminal to turn itself on. The S4 doesn't have an S terminal, the S5/6 don't have the R terminal

The S4 uses the L terminal as an output. When the alt goes bad or isn't charging, this terminal latches to ground triggering the idiot light. The S5/6 use this terminal as a turn on. When it sees voltage, it excites the alt.

The S4 doesn't have an S terminal. It uses the R to determine voltage regulation duties. The S5/6 have the S terminal and they use this to sniff the voltage to determine regulation duties.

Does that make sense, at all? Again, this is what I went through 3 years ago

[FC Zach]

Eh. . What makes the most sense is what I can see drawn out, like the diagram at to beginning of this page lol.

[FC Zach]

But yes, I see that there's difference in terminals and their requirements, please share your resistor size/part number. . I'm sure it could be beneficial to others as well.

So far things seem pretty clear as to what I need to do. . I just need to get it done. So with what you have said, I'm ditching the idea of searching for the OE wires and will run my leads like mentioned (I believe we're on the same page here).

[FC Zach]

Then, once I have the wiring done (I've been meaning to do this anyways) I need to get the alternator bench tested.

[FC Zach]

I'm checking that connector I mentioned. . It's a white/black wire that I believe I was using. . Checking it with a meter, it doesn't have power in any position of the ignition switch so I'll have to find another source.

What about this. . Use an unused 12v injector wire from my Ludwig harness for the "L terminal"? with a resistor of course. . What do you think? This would definitely be the tidiest route to take. Or would resistance on this wire cause any unwanted problem/s?

[TitaniumTT]

But yes, I see that there's difference in terminals and their requirements, please share your resistor size/part number. . I'm sure it could be beneficial to others as well.

I will do my best to remember to check it. If you don't have a text from me by 8pm tomorrow night, text me. It means I've forgotten

So far things seem pretty clear as to what I need to do. . I just need to get it done. So with what you have said, I'm ditching the idea of searching for the OE wires and will run my leads like mentioned (I believe we're on the same page here).

Then, once I have the wiring done (I've been meaning to do this anyways) I need to get the alternator bench tested.

I would do it the way I posted about for testing purposes only. Once it's confirmed that the wiring is good, and the alt passes it's bench test, you've run it and it charges properly, there's no electrical whine, there's no current draw on the battery and you can leave it for a few days/week with no ill effects, than I would start looking for the factory wires.

However, if you're using the factory wires that you find in the harness, a few things are going to need to change in the car itself.
First, the Alt relay that controls the idiot light needs to be addressed. The B/W wire on the S4 chassis needs to be connected to constant power. Both of which are easy enough

I'm checking that connector I mentioned. . It's a white/black wire that I believe I was using. . Checking it with a meter, it doesn't have power in any position of the ignition switch so I'll have to find another source.

That's fucked up. What's the connector originally for?

What about this. . Use an unused 12v injector wire from my Ludwig harness for the "L terminal"? with a resistor of course. . What do you think? This would definitely be the tidiest route to take. Or would resistance on this wire cause any unwanted problem/s?

It would be the easiest, but I would not suggest going about it that way only because of the potential problems it could cause down the road.

Factory it's the FE-03 connector that's on the front harness that houses the wires for the alt. Page 50-16 in the S4 FSM I would find that connector, find the B/W wire and see if that has voltage, if it does, there's your L circuit (originally R) Then it's a matter of finding on the same connector W/G wire and ohming it back to the idiot lights. If you find that connector you can then tap that into anything on the dash harness (stereo) that has constant power. This is the new S terminal on the S6 alt. That would do it as well.

[FC Zach]

I will do my best to remember to check it. If you don't have a text from me by 8pm tomorrow night, text me. It means I've forgotten

Alright, will do.

I would do it the way I posted about for testing purposes only. Once it's confirmed that the wiring is good, and the alt passes it's bench test, you've run it and it charges properly, there's no electrical whine, there's no current draw on the battery and you can leave it for a few days/week with no ill effects, than I would start looking for the factory wires.

Alright, currently have one wire (S Terminal) temporarily ran to the battery. "L Terminal" pending till I find the proper resistor and a switched 12v source.

However, if you're using the factory wires that you find in the harness, a few things are going to need to change in the car itself.
First, the Alt relay that controls the idiot light needs to be addressed. The B/W wire on the S4 chassis needs to be connected to constant power. Both of which are easy enough

Noted. .

That's fucked up. What's the connector originally for?

No idea, I'll share a picture of it later.

It would be the easiest, but I would not suggest going about it that way only because of the potential problems it could cause down the road.

Ten four


Factory it's the FE-03 connector that's on the front harness that houses the wires for the alt. Page 50-16 in the S4 FSM I would find that connector, find the B/W wire and see if that has voltage, if it does, there's your L circuit (originally R) Then it's a matter of finding on the same connector W/G wire and ohming it back to the idiot lights. If you find that connector you can then tap that into anything on the dash harness (stereo) that has constant power. This is the new S terminal on the S6 alt. That would do it as well.

I'll look into this

[FC Zach]

That's fucked up. What's the connector originally for?

Test connector? ? was secured to the backside of the fuse block bracket.
https://c1.staticflickr.com/4/3703/32340429603_acc7bbc5c5_c.jpg

Since this is out and it may not be wise to tap into an unused injector wire in the Ludwig harness, I will search for a different source later down the road. Till then I'll make temporary connections.

Oh, I took a picture of the resistors I have laying around. . What are the chances any of these are the right ones?
https://c1.staticflickr.com/4/3746/33114893026_1586e69a3e_c.jpg

[TitaniumTT]

Alright, will do.
Alright, currently have one wire (S Terminal) temporarily ran to the battery. "L Terminal" pending till I find the proper resistor and a switched 12v source.

Kewl

Noted. .
No idea, I'll share a picture of it later.
Ten four
I'll look into this

From the factory, that's where the two harnesses meet, down below the masters on the framerail

Test connector? ? was secured to the backside of the fuse block bracket.
https://c1.staticflickr.com/4/3703/32340429603_acc7bbc5c5_c.jpg

First thought was AAS and it does look like F-14, AAS connector, pg 50-80

Since this is out and it may not be wise to tap into an unused injector wire in the Ludwig harness, I will search for a different source later down the road. Till then I'll make temporary connections.

That's kinda what I'm thinking.
The Alt charge wire is going to either the fuse block or the battery itself. Either way running them with the charge cable, like the factory did, would be the tidiest way to do it. It's just a matter of finding the proper wires and terminating them in a tidy way.

Oh, I took a picture of the resistors I have laying around. . What are the chances any of these are the right ones?
[img]https://c1.staticflickr.

:rofl: Probably pretty good ;)

[infernosg]

The stock S5 setup had the sense wire (larger white/blue wire) going to the EGI fuse in the main fuse block in the engine bay. The field wire (smaller white/black wire) went to the light in the warning cluster as mentioned previously. I left the field wire alone but since my harness is so cut up I spliced the sense wire into the headlight power circuit. I figure the electrical load increased quite a bit with the lights on so this would be a good source to use to tell the alternator to output more juice.

[TitaniumTT]

Exactly 100% correct. Although... I would check the output at the post on the alt just to make sure that it isn't overcharging.

[t_g_farrell]

Heres a nice page someone did on the alternator swaps and wiring them up.

http://www.rx7.org/public/altxref.html

[TitaniumTT]

Ok, so I went to go take a look at the resistors that I set up.... I did a little heatshrinking over the resistors so I couldn't identify them that way, I should've just ohmed them out, I'll try that tomorrow when I'm back at the shop, in the meatime, Ohms law tells me to start with the 150ohm resistor that you have and measure the voltage at the corresponding pins as per the FSM. There should be 1.2v drop across them

[FC Zach]

I swapped my trans/clutch this weekend and since the power harness was mostly disconnected I went ahead and removed it completely. . thing is haggard to say the least. It wasn't hard for me to pull the loom apart to expose wires since the electrical tape was rotted and crumbled away. The OE alt. wires for the "T" shaped connector were nowhere to be found. .

With this said, I emailed Chris Ludwig asking if this harness is something he can make. . If not, does anyone have any recommendations on where to get this harness or have one made?

[TitaniumTT]

Really simple Zac, locate the FE-03 connector down by the mess over by the masters.

It's a 6 pin connector on the front harness. It will have a B/W and a W/B wire there. Pin them out to make sure they work properly. If they do, than any sort of connector to jump from the FE-03 connector over to the Alt will work just fine. No need for custom harnesses here, as much as I love them ;)

[FC Zach]

Really simple Zac, locate the FE-03 connector down by the mess over by the masters.

It's a 6 pin connector on the front harness. It will have a B/W and a W/B wire there. Pin them out to make sure they work properly. If they do, than any sort of connector to jump from the FE-03 connector over to the Alt will work just fine.
Thanks Brian! Regardless of whether I find a harness or not, I may do this. Just to clarify things, this is the wire I will run with a 150ohm resistor correct? What about a diode, I read that it's recommended if wired a certain way but I'm unsure if I need this if run to the wire in the connector mentioned. . . Schawry, I schtooped on deez thangz.

No need for custom harnesses here, as much as I love them ;)
Well, this is really more of a want than a need since the thing is in rough shape. There are exposed wire to the transmission connectors, busted connectors, broken wire/terminals at connectors, and unnecessary/unused connectors.

[TitaniumTT]

Thanks Brian! Regardless of whether I find a harness or not, I may do this. Just to clarify things, this is the wire I will run with a 150ohm resistor correct? What about a diode, I read that it's recommended if wired a certain way but I'm unsure if I need this if run to the wire in the connector mentioned. . . Schawry, I schtooped on deez thangz.

Cheers brotha!
Ok, I just thought of another option here....
Since the harness is fucocked right now, what you could do is re-task the leading coil wires since everything you need is right there :awesome:
The leading coil (and this is from memory so bear with me) has two wires that connect to it. G/Y and B/Y. The G/Y should be dead at this point in it's life however, the B/Y is off the main relay and will be hot with the key in the start and run position. So, the B/W wire can be used as the key hot with the resistor wired in place. Then since you're right by the battery anyway, you can connect the "sense" wire directly to the M6 bolt on the fuse block.
As a bonus you can replace the charge cable as well :)

Is your oil pressure gauge and low oil light still functional?

Well, this is really more of a want than a need since the thing is in rough shape. There are exposed wire to the transmission connectors, busted connectors, broken wire/terminals at connectors, and unnecessary/unused connectors.

In that case what I would do is take all the connectors off the factory harness and use some Deutsch DTM connectors to replace all the factory ones.

Also, aside from the reverse switch, the other two switchs are no longer needed.

[FC Zach]

Cheers brotha!
Ok, I just thought of another option here....
Since the harness is fucocked right now, what you could do is re-task the leading coil wires since everything you need is right there :awesome:
The leading coil (and this is from memory so bear with me) has two wires that connect to it. G/Y and B/Y. The G/Y should be dead at this point in it's life however, the B/Y is off the main relay and will be hot with the key in the start and run position. So, the B/W wire can be used as the key hot with the resistor wired in place. Then since you're right by the battery anyway, you can connect the "sense" wire directly to the M6 bolt on the fuse block.
I like this, sounds simple enough!

As a bonus you can replace the charge cable as well :)
I'd like to replace the whole thing, everything is brittle.

Is your oil pressure gauge and low oil light still functional?
Pressure, yes but oil level is disconnected.

In that case what I would do is take all the connectors off the factory harness and use some Deutsch DTM connectors to replace all the factory ones.
eh, I'd rather have this done by someone with all the tools and materials already in hand.

Also, aside from the reverse switch, the other two switchs are no longer needed.
True, I didn't have them connected on the last tranny.

[FC Zach]

Heres a nice page someone did on the alternator swaps and wiring them up.

http://www.rx7.org/public/altxref.html

I meant to comment on this last week. . . This would be a great write-up/how-to but that's assuming one has all the OE wiring intact, not the case for me so I'll be building from scratch.

Thanks for the info though, it did help.

[TitaniumTT]

I like this, sounds simple enough!
I'd like to replace the whole thing, everything is brittle.

30 yo wiring is crispy?!?! Say it isn't so ;)

It should be relatively simple, I can only think of 5 wires you needs. Alt charge, Alt control *2, oil pressure and oil level. They should all be on that FE-03 connector

eh, I'd rather have this done by someone with all the tools and materials already in hand.

Welp, you can go here (I've been doing business with Joe for a LONG time) and get the kits of the connectors https://prowireusa.com/c-76-deutsch-dtm-connector-kits.aspx

Just order them with the solid pins. Then you just need this little guy
https://prowireusa.com/p-1813-deutsch-dtm-mil-size-20-crimp-tool.aspx

True, I didn't have them connected on the last tranny.

There's no need. I just break the wires off at the switch.

[C. Ludwig]

.

[FC Zach]

^ Can't see on desktop or phone. . However I was able to see the shared pic from my email notification.

This it?
http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=17106&d=1489153450

[FC Zach]

I like that, is very useful. There's no gray area. . It is: Do it this way or this could happen. Pretty cut and dry, that's what I was looking for.

[FerociousP]

Hey Zach, quick note.

For the sense wire, you could technically run a wire from the B+ on the alternator to the pin, but the voltage at that pin is used as reference for regulating... If say, your battery is in the back, the voltage read at the battery will be less that at the B+ "output" of the alternator... This could make the alternator regulate the voltage .1 or .2 lower than it normally would in stock config, or what you would prefer.

so, its good practice to have that sense wire be at least a little bit down the line from the alternator... If stock its hooked up at the fuse box, its probably best to hook it up there.

[FC Zach]

Hey Zach, quick note.

For the sense wire, you could technically run a wire from the B+ on the alternator to the pin, but the voltage at that pin is used as reference for regulating... If say, your battery is in the back, the voltage read at the battery will be less that at the B+ "output" of the alternator... This could make the alternator regulate the voltage .1 or .2 lower than it normally would in stock config, or what you would prefer.

so, its good practice to have that sense wire be at least a little bit down the line from the alternator... If stock its hooked up at the fuse box, its probably best to hook it up there.

I sent my decrepit harness off with a request to have these wires run within the new one.

But yes, I have done that temporarily in the past.

[FC Zach]

Wasn't able to get a harness made however I did find a salvageable harness off a friend's parts car that I can make work and have done in time for DGRR. .

While pulling the harness off I looked for the illusive alternator connector that was thought to be on the charge harness and that I presumably had removed years ago. . That is not the case, I confirmed it's on the engine harness. Glad that mystery is solved!

https://c1.staticflickr.com/3/2880/33119434053_263c07aa42_z.jpg

[FC Zach]

I've already removed tape and unnecessary wires from the salvageable harness like CAS, trans switches, and oil pan sensors. Once LMS EFI returns my old harness I'll run my alternator plug/wires before re-taping.

[FC Zach]

I've been away on vacation for a week, I come home to see my package still hasn't arrived. . I sure hope it comes in within a reasonable amount of time to get the 7 drivable for the Gap!

[almoststockfc]

I would make other plans instead of hoping to get the parts.

[FC Zach]

I would make other plans instead of hoping to get the parts.

Not parts per se but my old harness I sent LMS, I will need to reuse a few things off it since Charles' spare wasn't complete. I sent Ludwig an email. . communication has been slow via email so if this falls through I'll drive the Celica again. We shall see.

[FC Zach]

Since finding that the S4 alternator wires (R & L) are actually in the engine harness and not the charge harness like thought previously, I traced the wires in an extra engine harness to the connector located in the passenger side footwell.

I depinned all but two wires on that connector and will run them to the S6 alternator, however I'll only be using the "L" terminal wire. I thought it would be wise to run the other wire for the "R" terminal in case I need to replace the alternator and decide to go back to S4. .

https://c1.staticflickr.com/3/2848/34110649056_a4f19e7a00_z.jpg

[FC Zach]

I depinned all but two wires on that connector and will run them to the S6 alternator, however I'll only be using the "L" terminal wire. I thought it would be wise to run the other wire for the "R" terminal in case I need to replace the alternator and decide to go back to S4. .

https://c1.staticflickr.com/3/2848/34110649056_a4f19e7a00_z.jpg

After redoing the harness and finally getting things corrected to make a happy alternator I found I still had a battery drain. . . I took the alternator to get tested and it failed miserably but this was good news in a way (the search is over, I hope). Unfortunately it was just too late for my S6 alt :nopity: the damage had already been done.

Reason why it was a wise choice to run that one additional wire? ? No S6 alternators in stock and were special order, S4 was next day :) So I got an alternator arriving in the morning just in time for me to have my car ready for DGRR.

Even after replacing the damaged S6, I don't think I'll be in the clear just yet. . . The "Charge" warning lamp doesn't illuminate with Key On/Engine Off and didn't illuminate while running with the damaged alternator. I'll check the bulb next.

[t_g_farrell]

It wouldn't be DGRR week without some drama Zach. See you in a few days!

[FC Zach]

Ha ha, see ya then!

[FC Zach]

Update. . The wires I added to support either S4 or S6 alternators do what they're supposed to.

With regards to this, it was because the S6 was toast. With the rebuilt S4, the idiot lights illuminated like they should:
Even after replacing the damaged S6, I don't think I'll be in the clear just yet. . . The "Charge" warning lamp doesn't illuminate with Key On/Engine Off and didn't illuminate while running with the damaged alternator. I'll check the bulb next.

Not wanting to give up on the S6 alternator, I rebuilt it by replacing the bridge rectifier and voltage regulator this weekend. I took it to Oreilly's to have tested and it passed! Success! !

https://c1.staticflickr.com/5/4220/34938830392_e5ea77683f_z.jpg

I'll be back in business without any battery drain (I hope!) and with a properly functioning alternator when I get the car running again. . .

[FC Zach]

Update, I received the harnesses I needed to get the car running this month and got everything all buttoned up. Since getting it running I reinstalling the S6 alternator and have periodically checked the battery voltage for any severe draining like before. . There is none, everything functions as it should so the car is back in business :)

Thanks to everyone for your input and assistance with this. I tend to make a mountain out of a molehill at times but that's usually because I have no idea what I'm doing and need guidance on some topics so thanks again to everyone for the assistance with this.