Expert: Rob Painter - 1/25/2009

Question
The heater blower motor was not working, a whack with a wrench would get it going. After about a week, the wrench trick wouldn't work. Replaced the motor, still not working. No voltage to motor. Replaced control module (used 93 sts), no voltage. Second control module(92 eldorado used), no voltage. Replaced module w/transister, under hood by heater core (used 92 eldorado, different appearance). Still no voltage to blower motor. The module under hood appears to be used only on eldorados and sevilles.If I were to buy it new it would cost about $185. The control module hundreds. I love the car it has 160k but runs very well. All fuses appear fine and the modules seem to operate correctly.Are there any fusible links or hidden fuses? Any tips or suggestions would be much appreciated.  Thanks Marlin

Answer
Hi Marlin,

I will admit I am not an expert on your problem. It appears as though you have checked a lot.

Here is what I know that goes back to the 1980s Eldos, Sevilles on the blower motors. The problem was that it either would not shut off or would not work like yours. I changed many modules under the hood because of this problem. I saw many where toggle switches with resistors wired in.

One thing I remember well. When ever I was at the Caddy dealer for parts I would see two or three of these cars with the hoods up getting new modules.

I think Cadillac has had this problem since the early 80s and stuck us all.

Run battery power to the fan and see if it works. That way you know the blower works for sure first. Check your wiring at the switch for power.

I don't want to tell you to spin the wheel and get the module under the hood, but I do know from personal experience that is a common problem.

I will tell you if the motor quits on either one of my caddys, it many not be right, but I will put a toggle in and have hi blower. It would be the cheapest way to go.

Good luck.

Let me know what happens.

Rob