1996 Oldsmobile Aurora. Numerous electrical issues, engine harness at firewall- replaced entire harness, corrected most other issues. work Checked fuses, No 2 and no 3 cooling fan relays.
With ohm meter checked control circuit wire for these 2 relays back to the pcm. Checked engine operating temperature according to pcm via obd scan port, above perceived fan cut in. Appears pcm is not signaling relays. According to wiring diagrams pcm should ground the control circuit in relay at cut-in and is not doing so.
Wire back to pcm is inactive according to ohm meter. Can not locate #1 cooling fan relay (other 2 under hood at rt front) to perform same checks on it.
Cooling fans will not run with or without a/c on and well above cut in temp. I would like to perform the same checks I did on the # 2 and 3 relays on the #1 relay but have been unable to locate it. Where is the #1 (low speed) cooling fan located? Any other conditions that will prevent the pcm from signalling the fan relays? It would seem that it is the pcm, but I would like to be certain. Thanks for any help you might provide.
Answer: The #1 (low speed) fan relay is on the rear of the engine compartment, left of the wiper motor. Make sure all fuses are good. There are 2 fuses in this system. This system can get a little complicated the way that all relays work with/through each other. Let me know if you need more help, KK
2001 Oldsmobile Aurora 3.5L. No codes (used a reader). Checked for broken wires- none- fan motors not burnt or locked up.
Question: Have no cooling fans op at all, even putting a/c on. Also a/c comp not engaging either think related. System is charged and on dash push button shows engaged.
Answer: Check the fan relays, there are probably 2 or 3 relays that control the fans. One of those could be bad or shorted out causing your problem. You could also have a bad PCM (computer) that isn't turning the fans on when it's supposed to. That would need to be checked out.
As long as you're sure the fan motors aren't bad, or you don't have a faulty connection, I'd look into those first couple things I mentioned. If everything tests good, you have a wiring problem somewhere along the line in the engine harness, or from the PCM. Wires would need to be checked for continuity and for being shorted to voltage or ground. If you have an open, you can always run a new wire, that's fastest and easiest.
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