Component compatibility, S4-S5

[sv51macross]

There's a S4 at a reasonably close junkyard. Figure, get as many compatible parts off it for Lucy as possible. Already grabbed the combo switches (different pin arrangement, same connectors, right?).

Going back for the manual belts (yes, I plan on modding stock interior), floormats, and the climate control logicon (future backup, according to Mazdatrix they're interchangeable S4/S5)
Now, my car is missing the radio (stolen). Is the S4 head unit (AM/FM/cassette) compatible with Lucy w/o major rewiring? I'll need to reattach the harness connector as mine is cut.

Is there some central list of interchangeable parts between the two series?

[NoDOHC]

Mazda had a couple different radios, even between the series. Some had a graphic equalizer and were different than the ones without. I sold the S5 radio without the equalizer a while back, but I am pretty sure that the connections on the back were different.

I have scrapped several S4s and S5s, so I just keep the series together.

Part number lookup is one way to tell compatibility (at the dealer).

I can't find it now, but there used to be a parts manual for each series on the internet that you could access to cross-reference.

You can also go to NAPA, etc. and see if they list the same part number for both series (works better for GM/Ford/Chrysler than for Mazda).

I wish I could help more.

[sv51macross]

Well, like I said, the miscreants who stole the head unit cut it off on the harness, so a new connector needs to be wired in anyhow. I'm sure between the shop manual, the Haynes manual, and an official Mazda wiring diagram book, I could figure out what wires go to which pins.

[RETed]

In short, most of the electrical components are not swappable.
Most of the electrical plugs have changed between the series, so it's not a drop-in swap.

With that said, why do you insist on the stock stereo components?
Unless you just want to resto or keep it nostalgic, aftermarket stereos are just superior in every way.
With the advent of MP3's, going with a modern head unit is a no brainer.
Aftermarket head units are CHEAP now - most are under $200 with great sound.
No need to deal with the stock wiring except to get power, +12VDC switch, and ground.
Run all new speaker wires, as your stereo system will thank you for it.


-Ted

[NoDOHC]

The only advantage that I have found with stock stereos is that they are not stolen very frequently out of a 20 year old car. Otherwise I completely agreed with ReTED.

[Pete_89T2]

FWIW, I've found that the following interior electrical parts are functionally plug & play compatible between S5 (recipient car), and S4 (donor cars). There are some cosmetic differences between the S4/S5 versions (i.e., how they look installed), but they all fit mechanically, plug in electrically and work as intended.

- Logicon climate control panel
- Air mix motor (for climate control)
- Power window switches

And to the OP's comment about retrofitting the S5 motor-mouse seatbelts with the standard 3 point belts from a donor S4, I wouldn't recommend it.

I've given that project lots of thought when I first picked up my S5 some 12 years ago, and concluded it wasn't worth the effort. In my case, I got used to the motorized belts, and they are covered under a lifetime warranty by Mazda due to a recall.

You may be able to *functionally* pull the swap off, but there are so many plastic trim pieces involved that making it look right (i.e., like stock) is next to impossible. Problem is the old used plastic trim pieces are so brittle they disintegrate on contact, plus the S4 parts were different, so there is little interchangability to begin with. You might have better luck finding an S5 donor car from a foreign market (i.e., Canada, etc.) that didn't require the automatic seatbelts. The other issues for a car registered in the US are of the legal & insurance variety - once modded in this way, it may be difficult/impossible to register and get insured. Or worse, you do get it registered & insured and find that if you get in a wreck, the insurance company won't pay out a dime and you're personally liable for damages because the car's safety gear was modified.

[My5ABaby]

Bare minimum to go from S5 to S4 belts you would have to change the A pillar, B pillars, headliner, and obviously the actual belts. I'm not sure if any additional holes will need to be drilled.

To make it look good you would also have to swap in S4 rear carpet and bins as the S5 bottom B-pillar plastic is chunkier. Also the center armrest is different, but interchangeable between series. To make the seatbelt swap look right I would also swap the console. The S5 center console is basically useless.

As for other electronics, the S5 and S4 idiot clusters are not interchangable without some repinning/rewiring. About 1/2 are different so the wrong things will light up. That said, if you want to go from early S4 to late S4 or S5 dash (different idiot cluster design) while keeping the S4 under dash wiring, all you have to do is flip the plastic cover upside down so the top is sticking out farther, rather than the bottom. Side note: also to go from an S4 to S5 dash you have to add a ground to the S5 dash. I can't recall where, all I know is there's a spot on the S4 dash and not S5.

The plugs for the lighting by the rear view mirror are different between series, although the wiring seems to be the same so it would be an easy swap. The sunroof wiring is the same.

The window switches are interchangeable.

[NoDOHC]

You do know that there is a lifetime guarantee on the auto seatbelts. I had the ones in the '91 done twice at the Mazda dealer for free.

[My5ABaby]

Originally Posted by NoDOHC

You do know that there is a lifetime guarantee on the auto seatbelts. I had the ones in the '91 done twice at the Mazda dealer for free.

You do know they're evil right?