Paul... cant thank you enough for simplifying this issue! I've had my qtr windows in the "up" position for years for a few reasons (too lengthy for here). This year I am finally fed up with them being up all the time. You are a Jag "savior", lol

 

Thank you Paul!
That did it! I would have never known.....

Marty

 

Marty,

No problem, glad you got it sorted!

PAul

 

Shop told me the motor is bad on my XJS 1993 convertible passenger side rear quarter window. They can’t figure out where to get a replacement motor or how to do some sort of fix to get it to work. Can anyone out there point me in the right direction where I could find a new motor or even a used one that I could trust to work?

thank you much!!!

 

TRY THIS, EMERGENCY BREAK AS IF YOU WERE TO PULL TOP BACK BUT KEEP IT LOCKED, NOW PRESS CONVERTIBLE TOP BACK AND ONLY THE SMALL WINDOWS WILL COME DOWN. E BREAK AGAIN AND C. TOP UP. FOR THEM TO GO UP, WORKED ON MY 94’ XJS AND MY CURRENT 96’- enjoy

 

I am intrigued by this method. But wouldn’t that stress the window motors since they are getting maxed out trying to lower a top that is locked down. I would think that would burn them up?

 

Louie71,

It's fine, there's no linkage at all between the window motors and the hood pump. The only connection is the ecu telling each of them when to run.

Cheers

Paul

 

Paul... can you please tell us frustrated qtr window people which the violet relays operate which side/direction?

 

JagRepair.com - Jaguar Repair Information Resource will have the electrical diagrams you need.

They will clearly show you which relay does what.

 

BenzJag has shown how his 'facelift' car was done. I have a 90 and have had both the motors apart numerous times trying to get them to both work with the computer that controls the top. I finally gave up and completely rewired the top and windows to bypass the computer totally. I rewired the top switch to talk directly to the 2 relays for up and down. I also added 2 switches mounted on the back side of the console facing the package shelf. They get power from one of the front window's power source and then are directly wired to the up and down relays for each side. I have had no trouble with either the top or windows since. I also used a heavier gauge wire than original.

Others have tried limit switches to prevent the windows from overdriving (which happened to me during bench testing). With the rewiring, the windows go down and up when I want them to. Also, the top is no longer dependent upon the handbrake being engaged. The computer took a signal from the handbrake before it would operate. The computer is too smart by half. It's supposed to delay the windows going up or down relative to the top's position (about 1/3 of the way open and about 2/3 of the way closed). Before, if the top switch even worked, one or both windows might, just might, work. I often found myself with 1 open and 1 closed. I tried a different computer from Paul's Jaguar that was supposed to work, but didn't on my car whilst my own did sort of work. I am thoroughly satisfied with my rewiring efforts and the freedom from a badly conceived computer system.

 

It's unfortunate that Eric had a problem with the hood and windows on his car. But the reality is that in over 20 years of XJS convertible ownership, I have never heard of or seen a failure with a hood ecu. And the reason is that it really does very little at all. It's a simple circuitry that looks for 2 signals, one from the handbrake switch indicating that it is engaged. And one from the rotary switch on the gearbox indicating that it is Park or Neutral.

With those conditions met, it just passes voltage when the hood switch is pressed, out to the window motors and the hood motor, via the set of relays. It doesn't know or care what position the hood is in, to fire the windows. When you press the switch to put the hood down, it passes voltage to the windows immediately, there is no delay. And when you press the switch to put the hood up, there is an 8-second delay before it passes voltage to the windows.

That's why you can leave the hood locked shut and still operate the windows up or down with the hood switch. The ecu doesn't care if the hood is closed, it still fires the windows, just with an 8-second delay when you raise them. The ecu really isn't that clever at all. You could just bridge the terminals on the ecu relating to the voltage signals from the handbrake and rotary switch and then you could operate the hood at any time. I wouldn't recommend that when you're driving quick as it can turn the car into a sailboat! Ask me how I know that!

Paul

 

Paul...checked your reference and found XJS page "under construction" no information