Good morning - I hope this thread is still monitored. I just started trying to troubleshoot the same problem on my 1999 3.4L Alero (cooling fans do not come on unless the heater fan is on - engine overheats, but temperature gauge reads reasonable temperature.)
Has anyone had any luck with solving this problem?
bnaylor3400 had mentioned that disconnecting the ECT would cause the fans to go on - I was thinking, since resistance in the ECT goes down as temp goes up that bridging the wires on the ECT connector (zero resistance) would cause it to turn on. Please let me know what you think.
Also, I believe it was the same person (you are a godsend sir!) that mentioned that the ECT sends a signal to the PCM AND the temp gauge on the dash - does this imply that if the temp on the dash is reading expectedly, that the ECT is sending a 'good' signal to the PCM as well? (i.e. my problem is NOT the ECT?) I am running out to my car at lunch to try disconnecting it!
I have already checked all the fuses, relays, wiring connections, and everything is good. I am starting to sweat and shake in thoughts that this may be related to the PCM. Please god. . .someone tell me its not something to do with the PCM. PLEASE!!
