i have a '92 rs heritage edition and just recently put a custom bulit 350 in it. Ever since the engine swap the fan turns on and off whenever it wants, sometimes causing my car to run hot. I bought a new fan switch, replaced the relay, and all connections are good. It always comes on when i turn my a/c on, but only sometimes without. Any ideas?

 

Two things to check...when you turn on the ac check power or voltage at the fan connectors itself and see if power is there.If it does then the fan motors are likely going out ...if not get a scanner and check the ac function.The scanner will tell you when the ac switch has been activated,if its not receiving a signal you have some electrical issues.It will also tell you if its low on freon,there is a code for it.Sometimes the fan(s) wont come on till the ECM sees pressure from a ac pressure sensor,might have a wait a few minutes once you turn on the ac.

 

thanks ill be sure to try that soon