Power Window Dilemma

I'm stumped. A couple of days ago, my wife told me that she lowered the passenger side window on her 98 Trans Sport, but that it wouldn't go back up. I removed the door panel and saw that there were only two wires to the motor, and that the motor didn't appear to be grounded via its case. I checked the electrical connector supplying power to the motor by connecting one side of the voltmeter to ground, and probing each of the two terminals supplying power to the motor. I found +12V on one terminal, and then the other, as I pressed the pw switch back and forth. Then I removed the motor from it's mount, reconnected the power connector, and pressed the switch. The drive gear on the motor would only turn one way (corresponding to down). I naturally assumed that the motor was bad, and replaced it with a new one. That didn't solve the problem. I don't think it's a switch since both the driver-side and pass-side switches produce the same result. Can anybody help diagnose this problem?

Well you must check not only that the 12V is present on one side and then on the other side when you press the button for up and down, but ensure that the other connector in each case is a solid ground: solid ground on one side, then on the other side for up and down. IN fact, you must check with the voltmeter connected to the 2 connector slots, not on chassis ground. I would think that you have a problem on the ground side. If the motor rotates, then there is no way it would not rotate in both directions if it is fed a solid 12V and a solid ground in direct and then in reverse polarity.
ANd yes, the final ground of the circuit in on the driver side, so it is normal that the pasenger switch would not work if the driver switch is the culprit.
I have a electrical schematic diagram for that at www.avigex.ca/xport/pwrwindows.jpg but at this very time the server is dead....so maybe later
..or Just e-mail me at [email protected] and I'll send you the diagram with a special indication for where to look for the culprit.

p.s. the avigex server is back on line now

I've had the same issue with my 1997 Trans Sport. Both windows go down but will not go back up. I replaced the switch module on the driver's side and everything went back to normal.

Thanks for the help, folks. The new driver's side switch set did the trick. I wish I had consulted this forum before I removed the passenger's side door panel.

I had the same problem last year with my '97. I replaced the driver's side switch , which was told is the master switch which controls both sides. About 6 months later, the passenger side switch ended up failing and needed to be replaced. Don't know if the master switch failing earlier had anything to do with the passenger side failing.