2005 XJ8L Rear Window

The driver’s rear window on my 05 XJ8L will go up or down only about 4 inches & stop. I have to continue to press the window switch several times to get to the window all the way up or down. Each time it moves only about the 4 inches.

​​​​​​​ I have reset the window by getting it all the way up (and down) & then holding the switch for about 15 seconds with no improvement. I have also replaced the driver’s master switch with no joy. It does the same using the rear door window switch itself. All the other door windows work perfectly.

Any help sincerely appreciated.

Richard