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Old 04-14-2010, 01:37 AM   #1
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Default Electric Fans not turning on

Hi - New to the forum.
I have a supercharged 96 Bonnie with 136k and recently noticed I'm starting to overheat slightly in traffic; 220F by the dash gage with the A/C off and only 65-70 outside, so I figure something is amiss. With the engine this hot I figure the fans should be on, right? but no they're not. Being an engineer and loving a good problem I did the following:
1) I put 12V across the motor and it worked.
2) I jumped the hi and low speed relays with a wire and the fans went to low/hi speed as I would expect.
3) I swapped the relays with the horn relay and tested the horn successfully, so the relays are fine.
4) I checked the hot side of the solenoid and that'* at +12 as expected.
5) all fuses are OK.
That leaves the PCM not grounding the relay solenoid.
is this possible?
What PCM pins go to the cooling fan relays?
what else should I check?

Any help would be appreciated, as it'* only going to get hotter within the next few weeks.

thanks
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Old 04-14-2010, 04:00 AM   #2
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Welcome! I belive there is a relay.That operates the fans.Others may know more.Also check temp switch near t-stat housing.
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Old 04-14-2010, 07:25 AM   #3
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Low speed fans come on at 216F and high speed come on at 228F. Higher than most of us are happy about. If you have a method of scanning, I'd use that to monitor the temps and watch the fans. More than likely they are working properly, but the programming temps are less than desireable.
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Old 04-14-2010, 09:35 AM   #4
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OK thanks for the info Bill
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