I replaced mine a few months back. The motor has 2 wires going to it - I believe the switch supplies 12v to 1 wire for up and the other wire for down. Since the vehicle is 15 years old, sounds like it's time for a new motor anyway. I purchased a new motor, but before I took everything apart I plugged the motor harness into the new motor to make sure everything worked. The motor can be completely disassembled - I found the old motor's brushes were completely worn and the commutator was all grooved from worn brushes.