Problem on my Olds Aurora
Year = 1996
Mileage = 264000 kms
Engine size = 4.0
dash lights = no
codes = no
work done prior = Numerous electrical issues, engine harness at firewall (replaced entire
harness, corrected most other issues) work done to repair = 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 temp 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 intact
according to ohm meter. Can not locate #1 cooling fan relay (other 2 under hood at rt frt)to
perform same checks on it.
Tech = KK
question = 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 & 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.
KK:
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
Year = 1996
Mileage = 264000 kms
Engine size = 4.0
dash lights = no
codes = no
work done prior = Numerous electrical issues, engine harness at firewall (replaced entire
harness, corrected most other issues) work done to repair = 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 temp 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 intact
according to ohm meter. Can not locate #1 cooling fan relay (other 2 under hood at rt frt)to
perform same checks on it.
Tech = KK
question = 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 & 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.
KK:
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
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Other related questions
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.
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.
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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