1999 xj8 driver window and sunroof quit working. we did some detective work and decided the window module in drivers door was bad,we unplugged it and plugged it back in and window and sunroof started working for three days! then it quit again. we unplugged module, plugged it back in and windows worked but crazy like the right rear button worked the driver window and so forth, so i purchased a used module off ebay (from where jags go to die) installed it and worked fine for about a month. now its the same trouble again, if i un plug and plug it up it will work for a day or two then same problem! any ideas or suggestions? it may be that the used module is bad as well? thanks to all for the great help this forum has been to me.,
These cars at times can be very temperamental and finding the problem may take time. Now that I got that out of the way you will need to dig in and find the problem. I am attaching a link for a oneline for your car. http://www.gusglikas.com/AutoRepairElectrical.htm and look at fig 15.1. Poor connections have been the cause of many of the problems and I would suggest that you look in that area, check plugs, connectors, power and ground connections related to that window and roof. In my 93 xj-s I took the switches apart and cleaned them, if only your problem could be fixed that easy. Just be sure to disconnect the battery prior to messing with the power system. I hope this helps!
XK8 1999 126,000mi K&N Filter, S-Type 2000 3.0 108,000mi K&N Filter
Insanity: doing the same thing over and over again and expecting different results.-Albert Einstein
“I fear the day that technology will surpass our human interaction. The world will have a generation of IDIOTS.” – Albert Einstein
I had no clue until you mentioned the rear window switch operated the front window. When weird, unrelated symptoms occur, i agree with gus on electrically related, though the first thing i recommend is a hard reset at the battery. I and others have had strange behaviors like this corrected by a simple reboot. Give it a try...cant hurt.
The driver's power window on my 1999 XJR periodically has been failing to go up or down for a long time. Switch and window motor generally test out okay. Problem always seems to be the window control module inside the door.
During the last several months, I’ve been through three different used modules that were tested and working before my purchase. In each instance, the module worked for periods of several days to several months before failing. A few weeks ago I read on this forum about rebooting the system by disconnecting the battery for five to ten minutes. The first time I tried this, it worked for several days. I then tried it again, and the reboot has now been working for ten days. I hope the window continues to work, but I’m doubtful because the battery reboot failed after a period of time for some other users of this forum.
It appears that the problem is not the control module, not is it a short or loose connection in the system because the battery reboot appears to always result in the module working again, at least temporarily, and it appears unlikely that a reboot could fix a short or loose connection. Another thread on this forum (99 xjr drivers window / sunroof electrical - Jaguar Forums - Jaguar Enthusiasts Forum) suggests that low voltage from the battery, possibly during cranking, may cause failure of the retention system in the control module. Does anyone know what the real culprit is?
My driver's window control module has been repeatedly failing since my first post here in May 2012. After a failure, I reset or reboot the system by disconnecting one battery cable for a few minutes. When I re-attach the battery cable, the window module works again. But it lasts only a few days to a few weeks, and then I have to reset the system again. Recently, I've had a battery switch installed, which allows me to easily turn off (disconnect) the battery and then easily switch it back on after a minute or two, thereby resetting or rebooting the electrical system. I just tried it a moment ago, and it worked fine. My driver's side window now functions again. But I've still not found out what is causing the module failures. Does anyone know the cause?