I am having a problem with the Driver's (left) Side Power Window on my 2006 XK8 Convertible .
When I pull the door handle, either inside or outside, the window drops about 1/2 inch (12 mm) as it is supposed to in order to clear the convertible top, and rises back up when the door is closed.
But about once a week or so, this stops working.
Then the window drops an inch (25 mm) and does not rise back up.
It is as if it has lost its programming.
If I re-program by running it down until I hear the click and up until I get the click, it is OK for awhile, usually about a week give or take.
It seems to have started a couple of months ago, when it got cold and rainy here (I am in Texas).
I searched other posts; I do not think it is battery voltage as I watched it for a few weeks and it is always above 12, usually 13-14.
I don't think its the door switch, because I would not think that would make it forget its programming in the first place and work OK for a few days after re-programming. But I could be wrong!
I was thinking power or a ground - I can't find the grounds on the car i.e. the manual is too vague about where they are.
Ideas or suggestions welcome.
Thanks

 

A malfunctioning micro switch in the door that controls the window was a common fault on some older XK convertibles.
Vector

 

Have you measured the battery voltage while operating the window? There is a 30a fuse feeding each of the window motors for some reason. Maybe that the motors draw a lot of current. The situation you describe is with the engine off. If you get into the 10.5v range you will lose your window programming.

Easy . . . stop by your favorite auto parts store and ask for a free charging/battery test. The load test on the battery will confirm or eliminate this as an issue.

 

I had the exact same problem. As ridiculous as this sounds: Clean and tighten your battery connections. "That" problem (at least) hasn't returned for many months.

 

As others have said, you probably need a new battery. This is one of the early symptoms

 

I didn't measure battery voltage when operating windows but I can check that.
Battery shows no signs of being bad, e.g. it does not seem to crank slowly and I have never had a problem with starting.
Do you still think it could be battery related?

 

on these cars, they can start fine but many of the components on these cars do not play well if the batt is weak at all. My money is on the battery.

 

Absolutely. The battery can still supply enough current to turn the starter well, but the voltage will dip too low during the starting process to maintain the integrity of all of the computers.

 

Very Good Point:
Absolutely. The battery can still supply enough current to turn the starter well, but the voltage will dip too low during the starting process to maintain the integrity of all of the computers.

It's often forgotten that AMPS and VOLTAGE are used differently, Electronics usually are Voltage sensitive while motors are AMP.

 

I have similar problems on my 2001 XK8 convertible. The windows rarely go up when I raise the top. If I'm using the door key, I have to get in the car and use the console switches. The windows usually dip down but not up. So maybe it's time to replace the original battery? Geez, I only got 15 years out of it.
Another problem I'll look to resolve is that the trunk opens from all sources except the button on the lid. A new switch did not help. We'll see what a new battery does for that.

 

A new battery won't fix your trunk button issue, see here how to fix that.


https://www.jaguarforums.com/forum/x...-button-74403/

 

Before replacing the battery take a look at the ignition switch after you take the key out. There is a tiny shutter that closes and that initiates a 'power down' after a short time to conserve the battery. If it sticks open once in a while the battery voltage will drop.

I suggest you spray the KEY with Duck Oil then insert and wiggle a few times. Then monitor it over time.

 

In fact - EVERYBODY should do it!

 

Thanks a bunch for the advice. I replaced the battery and the windows work like new. Up, down, dip, whatever. It's all good. And a special thanks to RaceDiagnostics for guiding me to the solution to my trunk button issue. That's fixed too.