Heater Fan Does Not Turn On

[vex]

Recently (okay, so I've been lazy) my heater fan/blower motor has not turned on via the logicon. I have pulled the fan and tested it directly and it functions. I know the fan works. I also hear the relay switch cycle on when I turn the fan on via logicon. The FSM states I need to check the blower motor circuit breaker, but doesn't list where it is or what it looks like. Any help or knowledge for that?

(FSM: 15-101--Body Electrical)

[ElTeeFauci]

To the best of my knowlege, its in the corner of the fuse box up under the dash.

[vex]

So I think I found it. It looks to be under the dash under the label of 'heater'. I pushed the circle in order to reset it. No effect but I think that just rules out it being bad (short of me pulling out my multimeter and testing it I'm not 100% on that). I still hear the relay kick on and off but get no output from the motor itself. I guess short of me going out and testing the various connections to and from the relay I won't know for certain.

[Rotary Evolution]

so the breaker was in fact tripped and the plunger was sticking out? if so check it again to see if it tripped again after retrying the blower actuation.

[vex]

Nope, the button was not sticking out. I've read instances where some trip the breaker and the button doesn't protrude, but pushing the button area in will reset the breaker all the same.

[Rotary Evolution]

swap the 2 circuit breakers and try again, if it still does not work i would check to see if power is actually getting to the blower motor or not and work back from there.

[vex]

Okay, so get this: I tested the fan out of the car directly connected to a battery and it works. I hook up my multi-meter to the terminal/wiring in the car and check voltage there; it works. I connect the motor and the terminal together and... it doesn't work.

[ElTeeFauci]

so the issue is in the wiring or a relay...

You can see voltage, but that doesn't mean that it can provide enough amperage to run the fan.

[vex]

Originally Posted by ElTeeFauci

so the issue is in the wiring or a relay...

You can see voltage, but that doesn't mean that it can provide enough amperage to run the fan.

Which is what I was thinking... but I don't have a means to measure any appreciable amount of amperage at the moment (I suspect I have some switches that are unable to handle the amperage required for a few other systems).

[vex]

So I finally got some time to measure the Amperage going to the fan. It's way low: 0.07A on full blast, or what should be full blast.

So where am I looking now? Is it a relay problem? Is it a wiring problem? Is it before or after the Fuse/Breaker?

[JL1RX7]

Start at one end or the other. Going to take some troubleshooting to get were the loss is. Also check the fan it's self. Make sure you don't have bad winding.

[vex]

I'm wondering if the relay has crapped itself. Although I hear it cycle on I get nothing more than voltage--no current. If I bridge the AC-connection I get the fan able to come on full tilt (granted it negates the variable resistor of the logicon, but it at least lets me drive the car now).

Unfortunately the FSM doesn't relate any information concerning the wires that run to the 5-wire relay in question. I know there's enough current to energize the coil. The wire leading to the battery has voltage and some amount of current--but when I bridge that wire and the wire that runs to the motor I get no movement.

[JL1RX7]

Originally Posted by vex

I'm wondering if the relay has crapped itself. Although I hear it cycle on I get nothing more than voltage--no current. If I bridge the AC-connection I get the fan able to come on full tilt (granted it negates the variable resistor of the logicon, but it at least lets me drive the car now).

Unfortunately the FSM doesn't relate any information concerning the wires that run to the 5-wire relay in question. I know there's enough current to energize the coil. The wire leading to the battery has voltage and some amount of current--but when I bridge that wire and the wire that runs to the motor I get no movement.

Check continuity of your wires. See what happens there.

[vex]

Originally Posted by JL1RX7

Check continuity of your wires. See what happens there.

Tried that. I have continuity to ground on B. I have continuity to Fan plug (if I remember correctly) R/Y. Since I have voltage with Key off on L to relay I think it safe to assume that it has continuity. I'll need to isolate and test the variable resistor from the logicon to ensure that it is grounding properly (I believe it is... but I don't remember 100%). If I'm imagining the circuit correctly I should be getting a variable resistance to ground via the logicon switch to alter the current throughput going to the motor.

[Rotary Evolution]

most likely it is the relay or the blower motor resistor(never had to check one so i can't comment on where it would be).