Recently purchased a beautiful jag 2008 xj8 with low miles. Love the car. Replaced tires and figured out a relay switch issue that was effecting headlights. I expected a few issues and Having a new problem now - none of the windows are working at all. Attempted the global on / off trick I found in earlier threads / discussions. Windows all went down and now will not come up at all. Do not have an owners manual (disappeared when getting tired replaced ). I can't figure out if it's a relay? If so - which one ?? Any insight or help is appreciated.

 

Check fuse 16 in the passenger junction fuse box first

 

Fuse was fine. Replaced it anyway and no luck. None of the Windows are working at all. What next??

 

Is there power at the fuse also does the Windows work from the door switch on the drivers door or the individual switches

 

Unsure if there is power at the fuse - I simple checked and replaced the fuse (which appeared to be ok but replaced anyway). None of the window switches are working. All four windows are stuck in the down position. Sunroof IS working however. What would we check next?

 

hi each window has a separate fuse and the switch works on a earth system the fuse for each window is fuse f37 f46 in the cabin fuse box these are for the front windows the rear ones are f40 f28 in the luggage compartment I can't see all of them blowing but check them anyway . You could try a hard reset you may need the radio code but not sure if you use them in the USA it's a simple procedure just remove the battery cables from the terminals and touch the cables together for 30 seconds then refit them to the battery this resets things back to factory

 

Fuses are fine and I have done the hard reset and still no power to the windows. I'm out of ideas

 

Have you got a wiring diagram

 

I have seen them online but they appear very complicated. Outside my scope of experience.

 

If you download one it will be a lot easier for you to see things when we try to explain things the one I have is quite simple

 

Possibly a problem with your remote do you have a spare key for this

vehicle?

Do the other functions work on the remote?

Replace battery in remote?

Have you read section2-10 in the Owner's manual?

Insert key in driver's door and turn to rear for 2 seconds to close windows.

 

Any update on the windows

 

Remote works fine. Does not require battery replacement. Global entry enabled Windows to go down, and they do not go up. Cannot drive the car as all windows are stuck in the down position. Fuses are ok. Tried the battery disconnect and no luck. Would there be any other relays or electrical junctions that feed the window motor? What am I looking for in the electrical diagram?

 

Each window has its own power to the motor and its own earth then it is switched by a earth from the switch on the door or drivers door and global open and close you maybe getting a permanent signal the front module so the window will stay down but that would affect the sun roof you need to get a door panel off so you can see what is getting a signal at the motor

 

Start up the engine (so as to raise the battery voltage a tad), keep it running for a few minutes, and then try raising the windows (while the engine is still running). If that fails, disconnect the negative terminal of the battery again, and leave it disconnected for 15-20 minutes. Then reconnect the negative terminal, and allow the powertrain module to fully reboot. Afterwards, try raising the windows again. If still no luck, check the earth grounds in the trunk (boot). You might also try examining the earth grounds in the front (behind the headlights) for looseness or fracturing, but I'm not sure that those particular grounds would affect the window operation (but would be for the headlight problem).

 

Fever bee, it sounds like you were able to fully open each of the windows and now they are stuck open. The sunroof opens and closes correctly. Global closing using the keyfob is not working.

Could you please confirm if you opened the windows individually or together, and whether you used the keyfob (global open), the driver door switchpack or each door switchpack in turn?

It would be highly unusual for all the window regulators to fail at the same time and just after each window was opened. A faulty driver door switch pack could potentially cause the symptom, but again would be very unlikely to affect each window.

I notice you have only recently purchased the car, so I am wondering if you are falling foul of the window anti-trap feature designed to prevent children getting their heads stuck in partially open windows? If the battery has been flat or disconnected for more than a few seconds it is possible that safety feature was not reset correctly.

I would start by disconnecting the battery for 15 minutes as sugegsted above. That will reset the anti-trap feature. Then reconnect the battery and then chose one rear window to work on fist. Verify that the rear window switches are not disabled from the driver door switchpack (the button with the red LED and the window picture should be off.) From the rear door push down and hold down the window switch for 5 seconds, then immediately pull up and hold up the same switch and listen carefully for the sound of the motor engaging. If the windows rises to the top keep the button held up for 5 seconds after it closes fully then release to reset the anti-trap feature. If the window does not rise but it sounds like the motor is trying than have someone else lift the window glass while you keep that button held up. (That's why you should start with a rear window, as the glass doesn't fully drop into the door.)

Based on what happens we can narrow down the fault if it persists.

 

Any results on this problem

 

Yes, I'd be curious to see the outcome of this too.

 

what was the outcome