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90 Lumina Auxiliary cooling fan problem


justfoo
06-04-2005, 09:50 AM
Does anybody know how to find the wiring diagram for a 90 Euro Lumina?
My auxiliary cooling fan wont run unless I pull its control relay and stick a jumper in it's place.
I need to be able to track back to which sensor is responsible to start and stop this fan.

richtazz
06-04-2005, 10:08 AM
try replacing the relay. if that doesn't work, the motor is probably drawing too many amps for the relay and the motor needs to be replaced

justfoo
06-04-2005, 12:36 PM
Hi Richtazz, thanks but I've already tried that, the relay works fine for the main fan, and if I just stick a jumper into the sockets where the relay sits (contact side not coil side hehe) the aux fan runs like a charm for hours on end, I drove all through the Okanogan (hot hot hot) in this manner with no trouble, it's just a pain remembering to pull the jumper when I leave the car for a while.
That's why I'm wondering if its not a sensor or something in the computer that's not turning on the relay, oh ya i did take a volt meter and there is no power going to the coil side of the relay.
Thanks for your ideas though.
DF

richtazz
06-04-2005, 12:45 PM
The secondary cooling fan is designed to come on only if the coolant temp exceeds 230 degrees. unless your car is overheating, the ecm is not sending a signal to turn it on, thus no power at the relay.

jeffcoslacker
06-04-2005, 01:07 PM
should be on with the A/C running though...

justfoo
06-04-2005, 01:56 PM
Hmm curiouser and curiouser.
So maybe a loose wire from the ECM to the relay coil then, because she sure do overheat without it !
Thats why I'm interested in getting my hands on a wiring diagram, don't want to have to tear every panel off looking for it. Unless the sensor to the ECM is pooched? The dashboard guage still works...

jeffcoslacker
06-04-2005, 03:54 PM
If that's a two-wire to the ECM's temp sensor, the fan should come on if you jump across the plug with the key on.

justfoo
06-04-2005, 06:08 PM
Not sure what you're saying there Jeff. I dont know what the ECM looks like and I had kind of assumed the sensor was an analog sensor ie ECM sees actual temp via the sensor, not a temp switch. I also dont know where the sensor might be located and being an electrician I'm a little shy about shorting unidentified wires together hehe.

justfoo
06-06-2005, 09:39 PM
Does anybody know how to find the wiring diagram for a 90 Euro Lumina?
My auxiliary cooling fan wont run unless I pull its control relay and stick a jumper in it's place.
I need to be able to track back to which sensor is responsible to start and stop this fan.
I guess no one knows where to find a wiring diagram for this vehicle?
Oh well.

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