I am having the same exact issue. 2005 XJ8 Vanden Plas.. Fever Bee did you ever get this resolved. Help!!!!!!

 

Any resolution to this issue. I am having the same issue.

 

It's a pity people never get back and post solutions. After 5 years I'm sure there must have been one.
I have exactly the same problem. (2004 XJR) When I bought the car the front windows were stuck down and dead. No sound of anything when you tried them.
Using the key "All Open" feature the rear windows and sunroof opened and now the rears are also stuck down.
Using the "All Close" feature the sunroof only closes.
Hard reset of the battery does nothing. Holding any of the switches for 5 secs, up, down or praying to Coventry while you bow before the prancing Jaguar, also has no effect. All fuses to the window motor assembly modules are good.
All switches, front and back, rear window lock have no effect. (Well, the red LED illuminates.)
Obviously the motors are good because they wound down.
This has got to be something that can effect all 4 doors. The Front Electronic Module effects all 4 doors AND the sunroof. It also has a CAN bus connection to the Driver Door Module and the Rear Electronic Module. The REM, FEM and DDM are supplied by the red 10A fuse F42 in the cabin fusebox. Mine is good.
Basically we have a situation where all window switches are disabled AND the "ALL Close" function is not sending a signal to any of the door modules.
There are 6 connections on the door motor modules. A ground, power to the fuse and the other 4 are all switching signals. Each window switch obviously needs to send either an UP or DOWN signal. Now, the FEM also needs to send the same to do the ALL Open/Close but strangely the FEM has its own separate 2 connections making up the total of six. Why it doesn't just use the same as the switches, I don't know.
I wonder if it's possible for the one of the wires that splits and goes to all 4 door motor modules from the FEM has grounded out or somehow got corrupted. It's either the Red or the Red/Blue one.

 

I think the window lock button is everyone's issue. Parts geek has one driver door window switch in stock, not cheap. A junkyard may be better. One here had a couple XJ’s.
But trouble shooting is easy. Pull the other door panels off. Check for 12 volts on the harness the plugs into the window switch. The other doors appear to have a simple window switch and appear to all be the same.
The window lock switch kills power to the other windows. Usually. May kill drivers too in a XJ.
If you pull the drivers window switch the window lock switch terminals may be accessible. I will check my car to see if the window lock works on driver window.

 

When you say "Window lock button" are you referring to the rear window lock-out button on the driver's window button door panel?
Why should this affect the front windows? I know it's in the same panel but electrically it should only be connected to the rear circuits. The wiring diagram on this in the workshop manual Fig 14.1 is very unclear.
As I read it, the 'rear window isolate' switch position is read by the Driver Door Module DDM. The DDM is connected to the CAN bus which indicates to the Rear Electronic Module whether the rear window switches should get power or not.
I don't need to rip all the door panels off because I know the rear windows are working. They just went down when I did the "Global Open". The problem is that NONE of the windows go UP under any combination of switches or Global activation.
My basic question is "What voltage values would you have to apply to the 6 connectors on a Window Motor Assembly?" Because nothing I do activates the window. I have the passenger panel off to do the door mirror.
I assume that I have the ground (black) and +12V (red/Brown) thick cables correct. But what about the two from the Front Electronic Module? (FEM)
The FEM has one red wire that goes to all 4 windows and on the diagram it's labelled "Enable". What its voltage should be I don't know.
I tried 12v but nothing happened.
The FEM activates the Global Open/Close. It only has two wires going to all 4 windows. So I assumed like the individual window switches that one was for Open and one was for Close. But if that's the case, how does it signal "Enable"? I was assuming "Enable" was a method to make all windows active or not and if it wasn't "enabled" then none of the switches would work.

 

Excellent posts here. I recently bought a 2005 XJ8, the sunroof worked but none of the windows nor the glove box worked. Battery had been dead, otherwise it drives well with about 114k miles on it. Found Fever Bee's description which fit us to a "T". Checked the fuses, ok. Checked the main driver window switch, power to the switch, ok. Using the key in the lock the windows all went down but would not go up. Sunroof worked. Followed xdave's plan, battery ground off for 15 minutes, checked all positive and negative connections at the battery, reconnected battery, window lock red light went on and off when we pushed the button as expected.

Sat in back, pushed one window switch down, held for 5 secondes, pulled up until the window went up, held for 5 seconds, and presto voodo, all the windows now go up and down as they should, and the glove box also works as it should. Sunroof continues to open and close as it should. THANK YOU for great advice and an easy-to-follow plan which in our case solved a perplexing problem.