Hi there, I have an 01 S-Type that has me puzzled. A few weeks ago my drivers front window started acting up, it would work some times but it was sporadic. Eventually it quit working all together. I replaced the regulator with a brand new unit and new motor thinking that was the issue. It didn't resolve my problem. I tested the plug at the motor with a test light and am getting power to both the up and down prongs, when I press the window button the drivers door control module clicks but the window will not go up or down. I am completely stumped and any help would be greatly appreciated. Thanks in advance!

 

This sounds like the switch contacts are corroded or just not making good contact. Spray some DeOxit-5 in the driver’s window switch (the little straw should get in there) and try it again. I’d also disconnect the back end connector and spray that out too.

 

You need to test the power to the motor with the motor connected, not unplugged.
Poor connections etc. will often only show up when the circuit is drawing current.
If the motor is disconnected and there is no current being drawn your test light may well work, but it may not work when current is being drawn.

The power for the door motor comes direct from the driver’s door control module. The driver’s door one touch switch is a low power circuit, the power switching is done in the module.
If it is any help here is a link to the 2001MY wiring guide:

http://www.jagrepair.com/images/Auto...x2022001en.pdf

Looking at the above it also shows a fuse in the motor unit, I guess this may fail if the motor is jammed??

Mellow

 

Thanks for the tips I am still at a loss on this. I went through all the connections and checked the wiring and haven't found anything, was thinking maybe the drivers door module was bad, but I get a consistent signal to the motor. up down and automatic functions are all making it to the window motor but the window motor doesn't' budge up nor down. I even replaced the master window switch but no dice. I've tested the motor on my bench and it is working as expected. But does not work in the car. I'm literally scratching my head.

 

Does the motor even try to move? For example, is there a brief grunt, even if nothing budges?

I'm wondering if something is mechanically stuck, such as a regulator wire jammed on a pulley, or the glass wedged in the tracks. In such a case, the motor would try to move but would stall almost instantly.

Not 100% positive, but I believe the control module monitors the motor's amp draw. If something blocked the glass travel (such as a hand), the motor would work extra hard and the amp draw would jump up. The module sees this, and cuts off the power for safety. In fact, I think this is how the motor shuts off normally at the top and bottom of travel. Not 100% sure on that, but I don't remember seeing any limit switches, but this may not be applicable to all years.

If my amp draw theory is correct, you could measure the amp draw on the opposite door. See what a good window motor draws in transit and then at the end of travel. Then measure the voltage under load, and see if the controller does indeed shut off the power at the end of travel like I'm thinking, even if you're still holding the switch.

Then compare that to the bad side. You mentioned getting a good signal at the motor. Was that with everything connected and the motor under load? If so, is the voltage present as long as you hold the switch, or is it just a brief pulse? Or was your measurement unloaded, with the plug disconnected from the motor?

 

I looked a little deeper. The 2003+ wiring diagram shows the motor assembly does have limit switches. The early models do NOT show a limit switch, just what appears to be a circuit breaker or similar.

I played around with the windows on my '02 this morning. I have a little voltmeter doohickey plugged into the cigarette lighter socket, so could watch system voltage respond to the draw of the motor. The engine was at idle, with the voltmeter showing 13.5 volts. I'd suggest hooking up a voltmeter so you can see what I saw. It would be very helpful for troubleshooting.

With the window in transit, system voltage dropped only slightly, maybe around 13.2 or so. This drop was just enough to tell me the motor was working, but not too hard. When the window reached the end of travel, but I kept holding the switch, voltage dropped briefly to about 12.8 and I could hear the motor stalling. This only lasted a split second, as I then hear a dull click from inside the door. This click must have been the circuit breaker opening up. Remember, I'm still holding the switch. As soon as the click occurred, voltage recovered immediately to 13.5. If I released and held the switch again, I'd get the same end of travel response in rapid order as before: motor stalling, voltage briefly to 12.8, dull click, voltage back up to 13.5.

I tried all 4 windows, and all behaved the same way. Maybe 10% of the time I would not get the click, and the motor continued to stall with voltage down to 12.8. I didn't want to hurt anything, so I released the switch.

You can compare your dead window to the other three windows for troubleshooting. The voltmeter was really helpful, so invest a little time to hook something up. If you can't find a convenient place in the cabin to pick off voltage, hook your test leads directly to the battery, and set your meter outside the rear window, facing forward. From the driver's seat, adjust your rear view mirror to see the meter display.

Also, make sure your battery is fully charged. If the battery has started to run down, it may not have enough oomph to properly drive the window motors. Certain types of DC motors draw extra current as voltage drops, so the breakers may be tripping too soon. Or if the battery is run way down, I think there is some logic that shuts off non-essential functions such as the power windows.