As far as I know, the only relay for the windows supplies power to the switches- they actually control the power going to the window motors, i.e. connect the motor + to - for up, - to + for down.

The switches are the usual problem- you'll find very pitted and burnt black contacts inside. They're silver- file them smooth and they should work fine. It is possible that the window won't work from either switch due to a poor connection at one door.

Take apart all the switches and clean them, and see what you get. Much easier in any case than delving into the doors.

A very fine screwdriver, such as jeweler's screwdrivers, will be of great help in getting the switch panel out, and the switches apart. Be careful of the snap-together tabs on the switches.
--
Rob Bareiss, New London CT ::: Roterande Fläkt Och Drivremmar!