I removed my AC and put a 200 dergree on fan switch in my car while installing headers. Now the drivers side fan turns on as soon as the car is started. It does not turn on with the ignition on and the engine off, only when the car is running. Anyone know how to fix this?

 

The driver side or primary fan is controlled by the ECM and the AC request from the control panel. It sounds like something got screwed up when the AC was removed. I'll look at my diagrams and try to figure out what could have happened. Dan

 

Huh, I just unplugged everything and pulled all the AC stuff out. Thanks in advance if you come up with anything.

 

ttt

 

I had to retrieve my Chilton manual, it's the one will many years of notes(and corrections). Believe it or not it does not show a dual fan setup for 87, but that's not surprising. I have an 89 and it should be very close. The ECM controls the driver side fan. The ECM also gets a voltage when the AC is turned on and will automatically turn on fan 1. After closely studying 87,88, 89 setups the only thing I could come up with is this. Did you remove any relays, specifically the compressor clutch relay? The only other thing I can think of is this. You have to remember with a lower temp fan switch when it turns on BOTH fans should run. The ECM defaults when it sees #2 on and not #1. It's the reason I changed mine back to stock and the reason I don't recommend changing. Trust me, you'll be replacing the alternator every other year. Is #2 fan on also? If it is pull the wire from the new fan switch and see if cures the problem. Let me know how you make out. Dan

 

Is the compresser clutch relay inside the compressor? I have not had it hot enough for the passenger fan to come on yet but it used to come on when I ran the AC. But now just the driver is on and it comes on as soon as the engine is fired up. Also, I kept all the relays plugged in that came off the AC/heater box so the only thing that has changed is unplugging the wires coming off the compressor. Let me take a closer look at the compressor.

 

Well, the connecters on the compressor are not removable so I can't really tell if thats the problem or not. Anyone know if unplugging just these will cause the driver fan to run all the time?

 

Ground the wire going to the ECM that was on this switch on the A/C line.

 

Sweet, thank you :hail: