I am having a problem that the radiator fan does not turn on. I have changed all the temperature sensors and the fan coolant relay. I have also checked all the grounds. Any ideas what could cause this problem? I have a 1997 Chevrolet Cavalier 2.2L. From what I've read, this seems to be a common problem for Cavaliers. I've installed a switch, wired directly to the relay as a temporary solution. But I will not be able to pass emisions test with this. I would like to properly correct the problem. Any suggestions?