i have my coolant fans programmed to come on early by a hpp. question is, sometimes they wont go on and the temp will rise in traffic. i check the relays and there are 3 cooling fan relays. can anyone tell me which each one is for. also i swapped a couple of relays around and the fans turned on and havent had problems could i have a bad relay somewhere?

 

I would say that if you swapped relays and the problem went away then you either have a bad relay(try to remember which ones you swapped) or you had a bad connection and solved it by unplugging and plugging relays. On the relays, one is for low speed or 1 fan and the other two are for high or both fans. Make sure all your ground connections are good . A loose or broken ground wire can cause problems too.

 

thank you very much. i will look into that!