Bspikes

Ok I need a little help here. I tried using the search and got nothing, maybe I am not using it correctly. The power window on my Passanger side has quit working. I thought it was originally the motor so I swapped in a known good motor. Nothing. Tested the motor out of the door, works fine. After a lot of cussing and testing, I have come to the conclusion that I have lost the ground for the passanger side window motor. If I ground out the switch it all works just fine. Take the rigged ground away and you get nothing. Any one have this problem before?? Any help would be greatly appreciated. BTW its an S13, 1991.