coolant fans

1991 BUICK REGAL
100,000 MILES • 3.8L • 6 CYL • 2WD • MANUAL
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SCOTTBORDEN
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my coolant fans run if i run direct power to them. i replaced both relays and that did not work. now i have what i believe is called a coolant sensor? i cannot find it on my car.do you think this is my problem? thanks, Scott
Mar 1, 2017 at 3:00 PM
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CARADIODOC
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What is the problem? Do the fans never turn on? Do they never turn off? Is the engine overheating?
Mar 1, 2017 at 3:06 PM
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SCOTTBORDEN
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they do not turn on. the fans that is. at idle overheats.
Mar 1, 2017 at 3:17 PM
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CARADIODOC
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You have two separate but interconnected fan circuits with three relays. Start by finding fan relays one and two. Pull them out, then check for voltage in the sockets. Each one should have twelve volts on just one terminal. Now turn the ignition switch to "run". You should find twelve volts to a second terminal in each socket. If you have twelve volts on those four terminals, try switching the relays around. Failure of two at the same time would be very unusual, but one could have failed a while ago and you might never have noticed it.
Mar 1, 2017 at 6:10 PM
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WRENCHTECH
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Hi Doc, Let me point something out here.
Make sure you are not looking for a problem that does not exist. This car is designed to get hotter at idle. The fan is not even programmed to come on until approximately 226-228 degrees which can seem very high on the gauge, but is completely normal.
Try unplugging the coolant temperature sensor with the engine running. That will probably set a code that will have to be cleared later. If the fan starts them, you do not have a problem.
Mar 2, 2017 at 4:23 AM