I have a 93 Lumina which has been reading hot on the in-dash temperature gauge, but would quickly drop back into the normal range if I turn on the defroster at fan speed 3 or 4.
There are two cooling fans. The other day, neither fan was running, in spite of the temperature gauge reading high.
Tonight, when I popped the hood and cranked the engine with the engine already warm, the fan on the driver's side of the engine came on. I turned on the AC to trick the other fan into turning on, and when I looked back, the fan that was originally running had turned off and the other fan never came on.
I then turned off the AC and the first fan did not come back on. I watched for several minutes for either fan to kick in, and they never did, in spite of the Temp gauge reading hot and the dummy light coming on. I know these are not the most reliable gauges, but if I can smell the engine running hot, I know the gauge isn't that far off.
Any advice? No one around here can tell me how to test the relays from the underdash fuse panel.
Steve