The problem is likely with the motor itself if you've got more than just a few miles on it. I had a similar symptom on my '96 a few weeks ago. It turns out the prob was that the spring that pushes the lower brush up against the armature rusted in two and allowed the brush to drop away and break contact. I just bent it so that I could reuse it and get a few more miles out of the motor. Zero dollar fix. You can trouble shoot that by running power and ground wires from the battery directly to the motor connector in the bottom of the door from the battery. If it doesn't spin the problem's in the motor. You'll have to remove the door panel and then the aluminum panel right under that to get access to the connector. That is what I would try before tearing the dash apart to trouble shoot the stuff that's in there. If I recall correctly thats what the Helms has you trouble shoot before the motor.