My plan is to clean out the motor with compressed air and connect the motor to the switch as it normally would exist in the car. Test with the switch using a non-resistive load a see if the motor operates as is should.
If it operates correctly, then put unit back together lubricating all parts and do a final test. If not, then continue and attempt to crack open the case.
My hopes are that the adjusting threads where gumming up the motor and causing it to bind. This would explain why the motor just clicked when trying to get it to go up/down.

Attached Thumbnails