My heat or ac doesn't work. Nothing turns on and I don't hear any blowing. I checked the fuses too. Any suggestions? The car is a N/A 91 FC, sorry if I'm leaving anything out.

 

Try the circuit breaker type fuse under the dash,driver's side.
Check the connections at the Logicon( heater/ac controls) and the Blower motor units itself.

 

http://www.cochran-racing.com/FSM/s5/index.html

The series five FSM has a HEATING AND AIRCONDITIONING section in the link above that has a pretty good way of checking things out. Meter required.

Two fuses have to be good. Then the two relays on the heater housing have to be good. Then the TRANSISTOR has to be good on the blower housing.

The power for the HEATER relay and the EX-Hi relay are from the fuses. The way those relays work, is for the LOGICON to put a ground on those relays. Then the blower may still not work if the TRANSISTOR is kaput.

IF it's just the TRANSISTOR that is bad, the blower will still work, but ONLY work when the slider is put to the far right to pull in the EX-HI relay.

One preliminary thing to do it check the fuses.........then key to ON, and put your hand on the two relays. Now move the slider slowly to the right. When you do, the HEATER relay should click.

When you move the slider to the far right the EX-HI relay should pull in and click.

So first download the HEATING AND AIR CONDITIONING section of the series five FSM and then do what I just described.

If the HEATER relay clicks and the blower does not work, and the EX-HI does not click when the slider is put the far right, then pull the EX-HI relay and jumper the LW wire to the R/Y wire with the key ON. Both of those are large guauge wires FYI.The blower should work if the HEATER relay clicked earlier. Proves the blower works and not much else.

To see if the realys are getting power just pull the relays out and check the light green/black wire at each relay has power. Should with key ON.

IF you have that, then see if the other relay coil wire is getting a gnd from the LOGICON when the slider is put to the right. Should. If not, LOGICON is suspect.

Also check the TRANSISTOR for a varing voltage from the logicon as described in the HEATING AND AIRCONDITIONING section of the FSM.

I think its the HEATER, WIPER and METER fuses that have to be good. IF your wipers and gauges work you know those wiper and meter fuses are good.

I attached a jpg or two as an example of what the FSM has in it for figuring this out.

 

Sucks for u joe!!

 

Thanks to both of you very much. Well, my wiper fuse was missing because those are broken too, they don't turn off and only stay at one speed. So I put that fuse in and the heater/ac turned on, just still no blower. HAILERS, I'll check out everything you said and thank you for helping me out. I'll let everyone knows what goes on, but in the meantime, does anyone know something about my windsheild wipers?

 

HAILERS,

I was posting in the other thread about the heat/ac blower motor. I've checked everything I know to check per the FSM and your help. My question is... why is my EX-HI relay working now that I have unplugged the blower motor? When the blower motor is plugged in the EX-HI relay doesn't click. With the blower motor unplugged, the relay will click like it's supposed to when the fan speed control is slid all the way to HI.

I have voltage at all relays and the blower motor.