Trying to track down a problem. The fiero ECM temp never gets above 210 (roughly) (v6) any rate, the gauge on the dash will slow work its way up to 260 sitting at idle. We have checked for air in the lines, seems good. The fan will not come on unless I force it by using the AC or something?

There's an actual 'switch' of sorts for the fan to come on. It comes on automatically when the A/C is activated, but it also activates when the car reaches a certain temp. It's pretty high - I believe around 230 degrees. Rodney makes a lower temp switch so it will come on at a lower temp.

There may be something wrong with your gauge itself. Does it peg far high when you turn the car on? Remember that most all Fiero gauges are 'estimators' more than anything accurate.

[This message has been edited by Fiero84Freak (edited 07-12-2009).]

Here is a pic of the fan switch along with the other switches and sensors on the lower intake.

So how would one go about making sure the switch is working correctly?

simple test, unplug the wire from the switch, and short the wire to ground. with key on, fan should run. if not, then could be the relay, so try the a/c to max, if fan comes on then, the relay is good and you have a wiring problem from the sensor to the relay.
if the fan does not come on with a/c set to max, then relay is suspect, you can swap it with the fuel pump relay right next to it to test. the relays are on the foward firewall, just behind the drivers seat. easiest to remove the drivers side vent to get at it.
if that does not resolve it, check the fusable link. location on that may vary depending on the model year. here is the 88 wiring:


they are all pretty close on the wiring.

[This message has been edited by tjm4fun (edited 07-12-2009).]

quote Originally posted by pcwentworth: Trying to track down a problem. The fiero ECM temp never gets above 210 (roughly) (v6) any rate, the gauge on the dash will slow work its way up to 260 sitting at idle. We have checked for air in the lines, seems good. The fan will not come on unless I force it by using the AC or something?

If it will come on with the AC but not when the temps hit 260, then it's 99% the sender switch in the intake. You can disconnect the wire and ground it. If the fan comes on, chuck the switch and get another one. You can get a lower temp sender from Rodney Dickman if you want one.

Edit: Just noticed Tim got you the info. That's what you need to do.

[This message has been edited by TK (edited 07-12-2009).]