Radiator Fan not working

Old 09-24-07, 06:41 PM
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Radiator Fan not working

My friend has a 97 Chevy Cavalier with a 2.2 motor, manual tranny and a/c. The fan does not come on at all. With my test light, I could not get power to show up at the plug on the fan motor. I went to the fuse box and the fuse is good. Also I tested the fan relay which is the same as the blower relay, by swapping them. They both work the blower, but not the fan. I looked at the schematic for the cooling system and the only other item I can find that may be related is a fan control. But I don't know the location of it or if that's even the problem.As far as I can tell, something is not telling the fan relay to open to send power to the fan. Any ideas?

Old 09-24-07, 07:17 PM
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Welcome to the Forums!

Sounds like a bad coolant temp sensor. This sensor tells the fans to turn on.


To ops check the fan, disconnect the plug and connect the pos and neg to the battery.

DOes the fan turn on when A/C is selected?
Old 09-25-07, 03:46 PM
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diagnose the fan control circuit first before buying a coolant temp sensor. with your diagram, go to the relay again and check for B+ on the heavy (probably red) wire. if that's good, jump it to the other heavy wire (black with a red tracer), this is the wire to the fan motor. the fan should run.

if this is all good, then again at the relay connector, check for B+ on the control side (green, i think) of the relay.

the computer actually supplies the ground for the relay coil which in turn supplies battery power to the fan motor. do these tests and if you don't get it (how it works and what's bad) then post back and someone will help you sort the rest of it out.

keep also in mind that the fan probably doesn't come on til around 230 F
Old 09-25-07, 04:20 PM
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And to add one more thing we discussed here - if the coolant is not engulfing the temperature sensor and is within an air bubble behind the thermostat, it may not give an accurate temp reading to the computer sending unit and cause fan to not come on. I went through that with my car (most likely).

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