the main cooling fan works for the first couple of heating and cooling cycles then will not work. i have plugged another fan into the car, tested the connections with a test light, nothing. the a/c fan turns on fine but is not enough to keep car cool. i have swapped all the relays (relays from another brat). replaced the temp sensor (the one on the radiator that turns the fans on). i am blown away, i am to the point of just wiring the main into the a/c fan circuit and just fixing it that way. right now I can't even go up the slightest hill with out it over heating. any help would be greatly appreciated.

thank you

Add a ground from the body/chassis to the radiator. My guess is you have a bad connection (ground) that gets hot from the current pull during the first few cycles then loses it's ability to conduct.