Originally Posted by lontimecoug
thanks, i was wondering if both fans operated at the same time all of the time, I have no overheating issues, i just noticed that only one fan went on when I had the engine running with the hood up
With the engine up to operating temps, turn on the A/C to Max, full cold blower on Max. That should trigger the Second fan to come on. You will hear the sound difference of the car at idle with both fans running.
If no fan, and your A/C works, check the relay. 4 pin relay would be power, power, ground 'Exciter' wire. The Exciter turns on the relay passing the positive side from one terminal to another.
If you just add power to the proper terminal the Relay will activate if good.
One OBD I cars when the cooling fans will not turn on do to lack of ECM signal you need to replace the ECM & Proms. Most parts stores sell you a ecm that you must re-use your proms in. The 1988-1995 OBD 1 W cars all have ecm issues for cooling fans.
I have on cars NOT worth putting a new ECM/E-Prom(*) in: run a wire on a toggle switch from the dash to the Exciter Terminal of the relay. Last one was a 1991 Grand Prix that would not turn on the primary cooling fan.
It is always best to repair these cars properly, and replace bad items. Yet if the car is on borrowed time and a might get crushed in a year, keeping the engine from overheating via any means is acceptable.