To share my recent (Sat/Sun) story with you . . . after testing, similar to what you were doing, I took my motor and regulator out. Direct battery voltage and ground to first one combination then the other. Nothing. Removed the regulator and repeated the above. Motor spun both directions. Put it back together after a little service and it is working fine. In my case, I had run the window down and it was bound at the end of its stop. By releasing the pressure it works. May have a problem later yet so far it is working properly.
Steve

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Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.