Cadillac Repair: Heat/AC fan, digital voltmeter, wireing diagram

Question
1998 Cadillac DeVille
Heat/AC fan motor works sporadically


Answer
Hi Delmas, Usually when this happens it turns out to be the blower motor assembly but a loose wire connection somewhere can cause the same symptoms. I would get a wireing diagram and digital voltmeter and find out if the power and grounds are ok at the motor. If so then it is a bad motor. If you don't have a speed voltage then look to the control head or wiring. Sorry I can't give you a definitive answer but the motor is expensive and not always the problem. Test to make sure first.  Bill