Buick Repair Questions? Ask a Mechanic for Answers ASAP
Since the motors work in the down direction, this indicates that the motor and the wiring are good. The window switch is bad.
With your voltmeter set on DC volts, turn the ignition switch on and connect the red lead to the yellow wire at the drivers window switch. Connect the black lead to each of the wires listed below. The meter should show 12 volts if the switch is good.
Left rear wires are:
Right rear wires are:
Let me know what you find