Today’s Zip Corvette technical question comes from Jim, who owns a 1990 Corvette:
I have a 1990 Corvette convertible with 350 and 6-speed that I can only drive when the weather is cool because I cannot get the cooling fan to run. The fan motor is good (works when voltage is applied) and I have replaced all of the temperature sensors and the cooling fan relay, but still no fan operation. What else could be preventing the fan from running?
Answer: Your Corvette’s main cooling fan is controlled by the PCM. The PCM sends a ground signal to the fan relay when it sees the desired temperature to run the fan has been met. You need to check the relay and make sure you are getting your battery 12V and ignition 12V when the key is on. With the key on, jump the ground wire in the relay. If the fan turns on, you have an issue in the PCM and it may be time for a rebuild. If it does not turn on, then your problem lies in the fan circuit between the relay and the fans.