I'm not sure if this should be posted in the "Cooling" section but, I own an 87' IROC-Z, 5.0 TPI, and I've had an issue with the cooling fans frequently not turning on. When I pull the fans out and hook em up to a battery, the work, so it has to be an electrical problem. I took it to a local mechanic, and he got fustrated after trying to hook up the fans to trun on with the ignition with no success. So he gave up, dumped the car back in my lap with the fans not even working at all now. I would appreciate any advice with rewiring the fans as well as explaining some basic wiring principals, seeing how wiring and electrical is completely new to me. Thanks

I cant teach you how to wire....but i can point you in the right direction on what you need to do now...first off you need to get it all back to stock configuration(wiring wize)...im going to take a good guess and say the reason the fans werent kicking on was because the coolant temp sensor that kicks on the fans was broke or reading wrong or not pluged in all the way...that would be my guess for the reason they didnt kick on...maybe the fan relay was also bad...


My suggestion is not to go back to that mechanic....inless you told him to wire it up like that....its not a good idea to have your fans run non stop...inless your drag racing your car or something...ive never heard of fans being wired up to the ignition...

Either way when you do get them wired back to stock config....here is a good test to see if maybe the fans arent communicating at all with the computer....do the normal procedure to check trouble codes....1: to see if there are any codes showing 2: it will also run the fans constantly while you have the jumper wire in there


That is all i can think of for right now....hope it helps

Were they not turning on or, were they not coming on at the temperature you would like them to ?

On an 87, the primary fan should turn on around 220°F.
It is controlled by the ECM. It should also run anytime the
A/C has been turned on (granted the system works). As said
above, it will run if you put the ECM into diagnostic mode
with a jumper as well.

The secondary fan runs off the fan switch located in the passenger head (rear between 6-8 exhaust ports).
It is neither A/C or, ECM controlled.
The fan switch turn on temperature is 238°F

This obviously a slightly high temperature but, the normal operating range of the engine can be up to 230°F. Many people think this is due to some kind of fan not working issue when it is really, normal.

IF the wiring to the secondary fan is still in tact,
simply unplugging the wire from the fan switch and
grounding it (with the key in the ON position) will make
the fan run.

If you can't get either fan to work, you'll have to do some hunting from there or, take it to a competent mechanic if you're not comfortable with digging in the wiring.


I would say the above mentioned mechanic is a dumbass.
Unless you told him to specifically stop and to not return the wiring back to its original condition (as is somewhat implied), there is no reason to leave them (the fans) in a total non-functioning condition.
I seriously hope you didn't not pay this dips--t any money. If you did and now the car is worse than when you took it there, someone owes you money or, some free labor to correct the issue. Or, just pretend it never happened and stay far away from that shop.

yeah, i didnt pay him squat. but, the fans wont turn on which is causing my car to seriously over heat. like the coolant tank was bubbling and steam was pouring out of it. but ill look for that switch