Pontiac Repair: 2001 Regal - power window problem, halogen bulb, diagnostic steps

Question
Hello Todd,

I am really stumped by a power window problem on a 2001 Buick Regal.  None of the power windows will respond to the master window switch or the individual switches.  I have done
the following diagnostic steps, but can't uncover the problem.

I checked the yellow and black wires at the master window switch and I got 12 volts on my meter.

With the ignition on, pressing any of the switch buttons up or down will light a 12V test light on ALL eight of the wires that send power to the four windows.  However, no voltage can be read with the volt meter probes on any of the eight wires.

Installing a new master switch had no effect.

With the ignition on, I ran a separate "ground" wire from the body of the car to the black wire at the master window switch connector, nothing changed.  None of the windows will work.

With the master window switch disconnected, I used an auxiliary battery connected to the switch wiring connectors and could power all four windows up and down with no problem.

With the ignition on and the wiring connector attached to the master switch, I attached an an auxiliary battery to supply power to the yellow and black wires and I could use the switch buttons to move all four windows up and down.

I removed the circuit breaker from the power window circuit and placed it in the power seat circuit.  The power seat circuit worked normally.

Thanks in advance for giving some thought to this problem.

Answer
Hi Ben:

well you did a pretty good job here of trying to narrow down the problem but you need to go a step further. Just using a 12 volt test light or a volt meter is not a valid test of the ckts to the master switch. You need to load down the ckts. use a halogen bulb and go across the yellow and black wires the Bulb should light BRIGHT. if not you have high resiatance in either one of the wires. if it does light bright then try it on the output of the switch for each motor go across the wires for the motor it should light bright if not the switch is bad. BUT when you have the bulb across the window motor wires also put a volt meter across it with the bulb the polarity should change for up and down meaning the meter should show + 12 volts and -12 volts if not the switch is bad. good luck :)