OK, I see now that you have a variable speed (duty cycle) type fan. This system is pretty much self contained in the fan assembly. That 3rd wire goes to the PCM and the the PCM commands the speed. The way this has to be diagnose is with a bidirectional, professional scan tool. You can command the fan on from the scan tool to see if it works but it is most likely a bad fan assembly.
Friday, August 20th, 2010 AT 11:11 AM