Head Gasket won't keep your fan from coming on, it is a sensor somewhere, or the fan itself may have shorted. If it works during the tests, then the fan is a no go. Also, try the Cooling fan Relay in the Engine Fuse panel, my fan started acting up and that seemed to be the cause of the problem for me. Need to get the wiring harness fixed on the red car, so I can test this on it too.juggalo said:so i'm on my 4th ECT sensor and now starting to think it's something else in the cooling system. so if ur fans don't come on and ur ECT sensor doesn't show up in the trouble codes and the fans do work during the test, then something isn't right. my thermo0stat was replaced in 2000 and my water pump and t-belt was replaced in 2009. i can't remember if a flus was ever done but i don't know. i'm thinkin my head gasket is gettin worse.