The window on my 2000 VDP will not go down today. It was working yesterday though and I've never had a bit of hesitation indicating it was starting to fail.
When the button is pressed, you can head a click from the control module. I stuck a meter into the connector and it does show positive and negative voltage when the switch is depressed for up or down.. I suppose the motor has failed; I'd guess the brushes are worn down? This is a part I do not have in my boxes of jag stuff as I've never had a failure on a window before. Any chance or disassembling it and finding a suitable brush replacement? Or shall I just find an Ebay unit and go with that?
Thanks guys!
Best, Dave

 

I have 3 running sedans (X308) and one of them does have a left front window INOP at times that I fix by disconnecting the battery and performing a HARD RESET.
The window functions for a few months until it happens again.
Don't know why but might be low voltage at the door module?
You can check the motor and wiring by trying the GLOBAL OPENING/CLOSING to see if it operates?

 

What in the wide wide world of sports! THANKS for that reset tip. It worked! Weird thing, the global key turn to bring down the windows did not work. Then after the battery disconnect and jumper wire for about a minute, reattached the battery cable and the window is working again!
I could not keep these cars going without this forum. Thanks a bunch for all the knowledge of the many contributors all over the world. Amazing!
I should start with a reset for just about everything!

 

The motor can be checked at the 2 large wires in a round hole at the fwd most of the door , you can use either a battery of battery charger and just reverse leads for up and down . This will be a high current situation , so precautions or extra test leads to bring work out to you

On mine ( X300 ) found on the driver door controller the connector pins lock bar was loose letting pins migrate away from contact

In the end you may have to tell controller the window full up by holding the up button a few seconds after it arrives and then it has learned / clocked

 

It's magic! Hard battery resets works for a lot of gremlins in these cars.

Try some WD40 or equivalent in the lock and down the stem of the inside lock button; then put the key in slot and turn it to lock (windows should rise); then in the slot and turn it right (unlock); the windows will go down. Should help. You can always remove the door card and clean the connectors -- a PIA; easier to do another hard reset! I had to do it about once a year or so on my last 01 (F35063); never, yet, on the current.

I think that on these old girls dirt and humidity changes effect the electrical connections.