So when I replaced my A/C compressor in the '88 GT I had to rewire it for the new two-wire switches, one for fan control and the other for high-pressure shutoff. My radiator fan hasn't been kicking on at all, not when the temp goes too high, not when I kick on the A/C, and not when the compressor switch should kick it on either. It spins freely, so it's not seized. Most likely culprits?
There are several parts that would interrupt the temperature on circuit and same for ac on circuit but only a few that would stop both.Both circuits send a signal to the fan relay.I would run a good 12+ and ground to fan pigtail spin to full speed almost instantly then come to a smooth stop when power is pulled.If you have 3 posts on the pigtail it is 2 speed fan so check high and low.If that is good check power and more likely the ground at the fan relay under the drivers side head light.The only shared part left is the relay itself.I can't find the schematic to test it but a new relay is under $10 and if signal is going in but not out you found the problem.From memory(and it's not always that good) the hot and ground are shared with the horn relay next to it. The signal wires are dark green,one with a stripe I think and the fan wires are easy to trace.Check for oxidation where the wire plug into the relay.I will look for that wiring schematic.
Just saw this is an 88 gt. Pretty sure the wiring is different colors and location on 88 and relays are not next to each other.The testing procedure should be the same.
The only 2 speed fan in Fiero was in 84. Relay wiring colors are the same from 85-88. 88 fan relays are made of unobtainium, they are different than 85-87. Horn relay is on the passenger side kick panel, not by the fan relay that is in the driver side headlight bucket.
Did the fan operate properly before the new compressor/switches/wiring change? Do you have the switches mixed up?
No, and definitely not. I've tested it and validated that the switches are correctly connected and grounded. If they weren't the compressor wouldn't run at all.
We have had similar issues after replacing the single wire pressure switches with the dual wire switches. Various configurations of wiring yields either a constant run of the cooling fan, or a failure to run.
And to add to what everyone else has listed. Also check the circuit board on the HVAC switches (on the dash). Those circuit boards can fail and keep the fan from turning on. Although you seem to have other issues. Just something else to add to the bucket.
And to add to what everyone else has listed. Also check the circuit board on the HVAC switches (on the dash). Those circuit boards can fail and keep the fan from turning on. Although you seem to have other issues. Just something else to add to the bucket.
Good point, the traces burn right off of the board. EZ to see and repair....
I have rewired 86 and 87 but all I know of 88 is what I have read.We have one vote the relay wiring is the same so if anyone can second it or give the right wiring chime in.If not this is what I have in my notes.
big red wire is hot at all times 12+ big black with red stripe + to fan when relay is closed brown with white 12+ in run position dark green with white is the control wire.When connected to ground the relay closes,fan on
If the colors don't match then we know the 88 is different.good luck.
I openly admit I was not 100% positive the wiring didn't change on 88, that is why I said to verify the colors match. Apparently according to you I am correct.You said the colors and functions are correct per your previous post but I don't see you list them anywhere.I see a dozen posts but no response to his question how to test the relay.I am sorry I correctly answered his question and did not insist I am the absolute authority on the subject. Not tryin to piss you off joe. Just havin a little fun.
But, I don't consider info that I post as a 'vote' on a topic.
No wire colors were listed in my post as I was not near a service manual to provide complete and correct information.
Hopefully the O/P will be able to solve his problem.
Thanks for the info on the relay. Last time I checked, they were cataloged, but no longer available. I'll have to grab a couple if they're now available.
Sorry, I dont have part numbers I can ask the fella ( the wizard, he's some old dude with tons of homemade test equipment in his shop near me) what brushes he used. I dont want to give you a wrong number even if he gives me it. I have an 84 and Im 95% positive we have different fan motors.
