Today the fan started up on its own and all was normal for several hours. Then it stopped again. I suspect the relay. Any other ideas? I may very well try my own repair. Access to the motor and module requires removal of the glove box. I was told by the dealer that the relay is in there somewhere, rather than on one of the two main fuse/relay panels. The dealer charges $125 an hour for labor, BTW! Frank
Cadillac has had their share of problems with the "power module" which is a transistorized speed control device which takes the place of a blower resistor. I can't keep SeVilles and DeVilles straight, but one or both of those models and their GM counterparts use a blower motor which has an integrated power module.
Look under the hood on the passenger side firewall for the blower motor. If it has three wires going to it then you have this design which is a high failure item. Aside from the typical GM failures in power modules, the motor is positioned near engine heat and can cause quick death. Even though your description sounds like the power module is intermittantly opening, this failure can be caused by the motor drawing too much current. At any rate, the blower is an assembly so test it and replace it if necessary.
While the blower is currently inop, check that one wire has 12v, one wire is a solid ground (
Thanks for your help. I am told I have an "intermittent short on the motor." I think this translates into a bad connection. The dealer disturbed the assembly today when he diagnosed it and it ran fine for awhile after that. It periodically comes and goes. When it "comes" it is fine in every way with full speed range.
I'll simplify the diagnosis. If you have three wires going to the motor connector, then replace the motor. That style has virtually everything that can go wrong in one assembly. Check the tension on the female wire terminals at it's connector to be sure they are tight and corrosion-free.
Toyota MDT in MO
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