It's gonna be the track or the motor most likely. Grease the track, check voltage to motor. Could be regulator clip, again grease. The only way to find out is really to open it up and check it out while it is working.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth