Hi there, I have just joined this forum to ask for some advice - I have a a 1999 Jaguar XKR 4.0. I have just returned from Belgium (to the UK) where I was on a car rally. Whilst there, I had a massive battery drain - 0.45 volts left after 36 hours being parked at the hotel. Another guest with an XJL had a spare battery which meant I could join the rally and drove most of the day with various stops and no issues. The following morning another battery drain overnight to the extent that there is no life when inserting the key in the ignition. I recharged the battery at a nearby Merc dealer and by disconnecting the battery each time I stopped we made it back to the UK without incident.
Recently the key fob has been playing up despite renewing the batteries, cleaning the contacts and re-programming. Today I took out the fuse for the central locking and the drain seems to have stopped. I will know for sure tomorrow. I know the module is underneath the fuse box in the boot (trunk), but cannot easily see the wiring, only the antenna connection . Does anyone have any advice on what to look for / do next? I have had the car for 4 years and never had this issue before.
Many thanks, Mark

 

On checking the battery this morning, the voltage was down to 9.2, after 12 hours, so I still have a significant drain. I guess i jumped to the conclusion of the central locking as that had been playing up. Any suggestions of where to start looking? I will also look at other posts on battery drain.
Thanks, Mark

 

You probably have the premium sound system and the amp in the boot is known to stop switching itself off causing the type of big drain like you have, so worth checking.

Otherwise you have to start pulling relays/fuses until you find the drain.

 

Thank you dibbit, I will try the amplifier and see what happens. I have found the boot lock was not activating the boot lamps but have fixed that now.

 

The other common problem is the little trap door on the ignition switch (literally where the key goes) gets stuck open. Then the car "thinks" your key is still in the ignition the entire time and does not shut itself off. This is easily fixed with either graphite-based product (watch out for black stains around your pants pockets) or a silicon spray.

You can test this theory in case the trap door problem is not obvious. On my 2003 Coupe, I need to activate the switch (key inserted) to be able to release the fuel filler door (the button next to the trunk release).

If you believe there is a more massive current leak, someone more recently reported a similar issue that ended up being failed alternator electronics.

Best of luck, keep us posted.

 

I ended up checking the current across the negative battery terminal to the earth lead and it was showing more than 3 amps. Removing fuse by fuse the current almost disappeared when I took the a/c compressor clutch out.
I then tried another relay and turned the a/c on. It did engage the clutch, noisily, bearings I guess and when I turned the a/c off it stayed on.
I guess I need a new compressor rather than trying a new clutch or trying to fix it. I know it is difficult to get off and new one on because I had one replaced on my XK8.

Thanks all for your suggestions
Mark