Radiator fan only comes on if I turn on the A/C or Heat!!?!?!

[jmslms]

I have had the same problem with both of my Jettas (86 and 88). They both have sat for over a year at one time before I bought them.

The radiator fan will only come on if I turn the A/C on or the defroster.
I have tried to figure out what the problem can be, I had replaced the temp switch on the radiator and the relay switch on the 86, but it still didn't fix the problem.

I just got my 88 carat and it is doing the same thing, but I wanted to see if anyone else has had the same problem and if they figured out how to fix it?? any help is greatly appriciated!!!

Thanks

[boschmann]

You should have a red/black, red/white & brown wire at the fan motor. Try connecting a jumper wire from battery positive to the red/white wire terminal on the fan motor (brown wire terminal will have to be grounded). Fan should run on low. If you connect it to the red/black terminal it should run on high. If the fan works, the problem is often with the fan connector itself.