You can also disconnect the window motor at the connector then run a test wire from the battery to note whether the motor turns. The motor has 1 of several drive gears that actually is what moves the regulator. The teeth in the regulator gets stripped or the motor craps out.

The regulator is specific to the door. Any regulator from a 126 81-9x will work as long as motor and regulator are kept together. You can look up the various gear teeth on this sie if you're interested. Cheaper to just get a regulator out of a yard.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.