I've got an interesting problem in my daily driver (94 park avenue ultra). When I bought it, the rear right window was taped up because the power window wouldnt work. i bought a new motor for it and took the door apart, and it turns out the problem was someone had removed the nuts that hold the window to the scissor arms off, so i put some on and it moves ok now. the original and the new motor both work, but they only go one way. if i press either the driver's door switch or the one on the door up, itll go down, but nothing will make it go back up. What would cause it to do that? Could hte switch be bad, or is it mis-wired or something? Thanks for the help

 

The up/down on the window motors is just a change of polarity. You might find wiring help in a Buick forum.