Re: '99 power window trouble
Start by removing the LR door panel, leaving the LR switch connected for the tests. Try to lower the window with the switch while tapping the inner door shell with a hammer. If the window starts working, than you have a weak motor. If there is also a line of black dirt at the top edge of the window then you should clean this off and operate the window more often. Not using your window often enough causes the dirt on the weatherstrips to partially bond the window to the weatherstrip. If banging on the door doesn't work disconnect the window motor connector. Using a test light connected to ground check for power in the up and down positions on both pins of the motor. You should have power on one pin in up and one pin in down. This should be a start.