Cadillac Repair: climate control on after car offYEAR and MODEL ?., climate control system, heater fan

Question
what would keep it on    ????a relay  bad whitch and where 1989 cad, devillehhjy8
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One day we turn the car off an the heater fan (I think) any way some fan to do with the climate control system would not go off
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YEAR and MODEL ?.

Answer
Replace the BLOWER MOTOR and the POWER MODULE.

The POWER MODULE is located above the blower on top of the big black plastic housing that the blower motor also inserts into. The MODULE has a multi-wire electrical connector and a single large BLACK ground wire and is held in place by 3 7mm screws. When you remove it you will see a large aluminum finned device attached to the bottom which is used to cool the module.

Replace BOTH the blower motor and the power module.