I am trying to bring a ’96 850 back to life after sitting in a damp environment for a few years. None of the four power windows work. I have power at the main switch box on the center counsel, and power in BOTH lines going out to each window when I flip a switch. My question is, does one wire raises the window and the other lowers it? If so, I have a bad switch box. If not, I have no idea what the problem is.

 

Both wires lead curent depending on the position of the switch (up or down).
The blue thicker wire at the center console has +12V when you switch the key into position I. The black one is ground.
The motors are directly wired to the control unit no further relays or so are used.

 

Both wires between switch and motor should be 12v+ and depending on which way you rock the switch, one or the other becomes ground. You may have seized regulators.