Cadillac Repair: fan inside deville stopped?? Fuses okk ??, jumper wires, purple wire

Question
Have 1987 deville. During recent long trip fan stayed on when ignition was turned off. Air conditioning and fan ok on return trip home. Fan turned off ok when return home, but will not come on again.... compressor for air seems to run but not fan. All fuses seem ok. What could I fix or check next please? Thank you. James
No known prior problems with this.

Answer
Hi James, This could be a loose wire somewhere but most likely the blower motor is useing too many amps to run and that caused the power module for the blower motor to go bad. Start by testing the amerage draw of the motor by unhooking the connector at the motor and make jumper wires so one side(black wire) on the motor goes to ground and the other wire(purple wire) on the motor hooks to a 10A fuse and then through your meter to the battery positive. A good motor will use around 5amps to run and a bad one will blow the fuse. If it does then replace the motor and fan module which is in the same housing as the motor but on top and to the passenger side under the hood. Hope that makes sense. Bill