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Question

The electric radiator fan quit working on my 94 Chevy Corsica 6 cylinder. In order to test the fan I thought I should unplug the 2-wire plug from the sensor that is screwed into the block and jumper the 2 wires together at the plug to see if the fan comes on. Am I on the right path with this? (I replaced the sensor last year so I doubt that it is a bad sensor)

It seems to me that the sensor is merely a thermal switch that "shorts" when the engine coolant gets hot (to make the fan come on) and that by jumpering the wires on the plug I am simulating the switching action of the sensor. I don't want to actually do this without first knowing what you guys have to say about it. Thanks for the help.

bobj · Accepted Answer

You ought to first go to the library and look up the circuit  in their Mitchell's manual section...

W. Stief · Answer

Short form: Don't do it

Long form: the CTS is a varistor(?), shorting at the plug could damage the body control module. $$$

check the switch at various temps with an ohm meter.

Or just try a known good CTS.

aarcuda69062 · Answer

Wrong answer.

Negative temperature coefficient thermistor.

Someone should tell that to GM because it's part of the diagnostic routine and has been since 1980.

BTW, that car doesn't have a body control module.

Check the sensor at various temperatures with a volt meter (voltage drop).

Paul · Answer

Yes you can jump it, however I would start with the fan itself. That car is old enough to have worn the fan brushes down to nothing.

tj_fleming · Answer

I agree...a low amp probe and scope should be all you need to confirm poor brush contact.

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