My wife's work colleague has a 2004 XK8 convertible. She's owned hers about a month longer than my wife has owned her 2006 XK8 convertible....

For the last week or so, instead of the windows slightly lowering when the door is opened and then fully raising when the door is closed, the windows have been sporadically lowering halfway or more when the door is opened and then staying there when the door is closed. She claims that she found the window re-set procedure in her owners manual, performed it, and it worked properly for a few days, but then it returned to its previous malfunction....

Also for the last week or so, the car's alarm is randomly and sporadically sounding off. It may occur when someone walks by in close proximity, or it may occur when no one is around. Days may pass between these false alarms....

From my years as an S-Type owner I know that when the battery begins to die, all sorts of electrical strangeness can and will occur. I do not know if this 2004 XK8 still has its factory battery. Has anyone encountered these issues in their XK8, and if so, was the fix indeed a new battery?

 

I had something similar happen to my windows last year, but only later in the year when the evenings started getting cooler. Batteries don't perform as well when the temperature drops. When I would leave it on the charger overnight, the problem would go away. Mine is an '03 with the original battery, I haven't replaced it yet because it's been in storage over the winter.

 

A new battery should be all you need to fix the window/alarm problem, as long as there's no quiescent current drain, which would drain a new battery also.

 

You're on the right track Jon, it'll be the battery unless something else is pulling it down.

 

I would be really surprised if that was the original battery. The battery in my '06 which of course was built in early 2005 was replaced in Sept. 2009.

 

Jon89,

If you've got a digital voltmeter, you can get a pretty good measure of the battery condition, be it new or old. Procedure for doing that found here.

Good luck.

 

I guess some batteries last longer than others.
Only replaced my original battery 2 months ago. Varta manufacturing code for Nov 2003.

 

Where on the battery is the Varta manufacturing code?

Graham

 

Hello Graham

On the Jaguar one fitted to my car it was stamped into the lead, on top of the negative terminal, week number and 2 digit year.48 03

Had to gently clean the terminal, so as to not remove the numbers, and angle the light just right to see it.

 

Derek,

Thanks - I'd been all over the label and the plastic case looking for a code but never thought of looking on the terminal.

Graham

 

Thanks to all for contributing here. My wife will tell her colleague today that her car's symptoms point to a failing (or draining) battery. It will be up to her colleague to decide whether to have her current battery tested (keep in mind that failing batteries sometimes pass the routine tests) or simply replace it with a new one....

And yes, these batteries last considerably longer with proper care. Our 2005 S-Type still has its factory battery. I check the cells at least every couple of months and add water as needed. Our 2006 XK8 also has its factory battery, and its cells also get checked every couple of months. Both batteries are still running strong....

 

It could also be a sticking micro switch in the door latch. Of course, we all know it results in the window not going back up when opening the door, but what if it is intermittently sticking, then returns when the car is locked and armed...security breach (just like if you opened your car door from inside while the top is open).

One test to rule out battery, do the windows act up (do not return each and every time the door is opened) when the car is running?

 

The owner gladly took our information and made the decision to replace her battery two evenings ago. No problems reported since the new battery was installed. I'll keep the sticking micro switch in the door latch idea in mind in the event that the same issues return....