I suppose I could study the wiring diagrams but its more fun to ask here... The fan is not coming on in my 86 coupe, I suspect the relay. There are two relays on the driver side front by the headlight. One is on the side rail, the other is on the front bumper rail. Which one runs the fan and what does the other one do?

The one on the very front behind the bumper is the cooling fan relay. The other relay on the side is your primary headlight relay...

It's the large relay down below and in front of the left headlight. You might be able to
remove it with the headlight up, but I had to remove the headlight assembly to get to
the relay the easy way.

Does the fan come on when you turn on the A/C?

http://www.rockauto.com/catalog/x,carcode,1249095,parttype,3060

Ok, so I started testing stuff. The fan works, and the fan relay works. So much for the easy fix! I topped off the coolant, burped the system, and let it run to get to 220. Then tested the fan coolant switch, infinite resistance, (open). I figure that must be bad because the car had been overheating and I have noticed the fan not running. As long as the car is rolling down the road, the temp stays below the red, but when stopped, the temp climbs.

I went to Autozone. The parts guy to tried to tell me that the temperautre sensor he pulled from the back runs the fan. I told him no, because the temp -switch- is a one wire deal, not a two wire, and that there are three temperature devices on this engine. After convincing him to dig a little more he did come out with a one wire device that looks like it will fit except the electrical connector is not right, its a spade, not a round coax looking thing. I go to Checker and they dont have anything in their system. Finally, Im looking at the Fiero Store and they show a 4 cyl switch, and 3 choices for v6 switches. The 4 cyl switch with AC does not look like mine (even though I have AC). Mine looks like the v6 ones and the 4 cyl w/o AC as far as the conector goes.

http://www.secureleadercom.com/fsstore/default.asp?searchBit=1&searchType=t&searchString=fan+switch&howSearch=AND&searchfield=inetsdesc

Could the difference be between the single speed fan and the dual speed fan on that 4 cyl with AC swicth? BTW I have the single speed fan.

So Im interested in the 185 fan switch. It says for v6 but looks like that should work. Do you agree?
Then I think I might go for that 180 thermostat. Advice?

Thanks Everyone for your help.

the 84 ac siwtch is for the 2 speed fan.
the other one is the same as the v6.
don;t do the 180 tstat, it will hurt your mpg. leave that at 195, and get the rodney dickman fan switch that comes on at 210 I think it is.

hey indiana_resto_guy ,what if the fan dont come on with the a/c on,mine doesnt come on with the a/c,whats the cause,sorry to bust in ,but this would answer my problem ,thanks keith

quote Originally posted by interceptor429: hey indiana_resto_guy ,what if the fan dont come on with the a/c on,mine doesnt come on with the a/c,whats the cause,sorry to bust in ,but this would answer my problem ,thanks keith

Then you jumper the fan to check it's condition, if it runs, replace the relay. If it does not run, replace the fan motor.

quote Originally posted by interceptor429: hey indiana_resto_guy ,what if the fan dont come on with the a/c on,mine doesnt come on with the a/c,whats the cause,sorry to bust in ,but this would answer my problem ,thanks keith

First, unplug the wire from the fan temperature switch on the engine. Ground the wire through a clip lead or a piece of wire.
Does the fan come on then? That verifies that the relay and motor are good.

The A/C control head has a printed circuit board on the top. Occasionally, the trace that supplies the "turn on" circuit for the fan relay will burn up.
This circuit is essentially "teed" into the wire that comes from the temperature switch. Either one can turn on the fan, independent of the other.

I forgot about looking at Rodneys'. After thinking about it too, I would rather the engine run a little hotter, it already runs on the rich side (all the mods I did) so I should stay with 195 stock thermostat. Then going with Rodney's 210 on and 200 off switch should keep the engine in better control closer to that temperature range, if it indeed operates in that range.