Heater not working on High mode on Buick LeSabre Custom?

This problem is faced by many others too.There are 2 possibilities.
Either is faulty/weak blower motor itself or its controller.
When motor gets weak,it will work on low settings but not on high mode.
But if motor is checked ok,then
You need to replace the blower motor controller.
It is on top of the underhood blower case just right of the blower motor.

This will help.

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