Questions and Answers

Cadillac Blower Motor problem Q. Hello! We have a 1987 Cadillac Sedan DeVille. 4.1 engine, automatic transmission, 130,000 miles, fuel injected, ABS, in very good shape... except for a heater fan that stays running and will only shut off when its disconnected from the battery, and will stay off until turned back on and then goes to high again. Help!!!

A. You probably have a bad blower motor Power Module. Now, since this is a Cadillac and nothing simple is done unless it can't be made so complicated that a rocket scientist would scratch his head, testing it can be difficult.

The Power Module may go bad in and of itself, or the A/C compressor or blower motor may burn it out, so replacing it out of hand may not solve the problem. The procedure to test this is a little involved and is something only an advanced DIY or professional should do.

The engines Powertrain Control Module (PCM) is also a part of the Electronic Climate Control (ECC) so the best thing to do is to take it to a Cadillac dealer and let them diagnose the problem.

Additional Information provided courtesy of ALLDATA