Battery drained, why and next step?
 

2002 XKR needed AC work. Mechanic changed compressor, refilled and AC worked great. Drove home in stop and go traffic for an hour. When I got home I parked and turned off the ignition. I went to exit and close the door and it wouldn't shut due to the latch not staying open. I the noticed that there was no power, like a dead battery. I could see a dim warning light in the dash but don't know which one. Car would not jump start and is dead as can be. The battery is old and could be the problem. It had never been driven with AC on and an hour of stop and go in the Texas heat. I will purchase a new battery but are there step to reset or any other advise, words of wisdom?

Get the battery and charging system analyzed, you probably have something not working right in it. If it won't jump start, you may have a dead or broken cell in the battery.

There are a couple of things to reset.
1 The window settings. Open the window and hold the button a few seconds until you here a slight tone then close the window and hold the button again until you here a tone. The windows will now be reset.
2. You will need to reset the seat memory.
That's about all there is to it.

Once you have the new battery installed and the engine at idle turn on everything. A/C full fan, heated rear window. lights and hazards. Then check with a multi-meter across the terminals of the battery insure you are getting 13.5 to 14 volts. That makes sure the alternator is working.

You don't mention if the vehicle is a daily driver, garage queen or somewhere in between so it's impossible to determine whether this issue can be expected or is very unusual.

The obvious place to start is testing the battery as this is the number one cause of weird electrical phenomena in the V8 Jaguar models. However, the total failure after a lengthy drive is unusual. A partially discharged or failing battery will usually be sufficient to power auxilliary functions but not to start the vehicle.

Check the HPPM (High Power Protection Module - see item 5):

https://cimg3.ibsrv.net/gimg/www.jag...d05271b21c.jpg



The cables are known to work loose or partially break and this can cause the behaviour you describe.

Graham

Positive battery cable at HPPM
 

+1 to above comments esp. GGG’s comment. Zero dollar check/fix on HPPM.

The positive battery cable connects to big fuses at the HPPM. Connection should be grit papered cleaned and shiney and sprayed with contact cleaner not WD40 and bolted tight.

If you can get the car running, maybe do a quick check of voltage on the battery - should be approx 14V to ensure alternator is charging the battery when running.

Update: The battery appeared old and the date of service could not be determined. I dropped a big brand new battery in her and she rides again. Hearing the difference in the starter now makes me realize the old battery was tired. "Dolly" lived in the backwoods of east Texas the last five years or so and didn't get out much. She was depressed had low self esteem. With a little attention, new shoes, and some make up, her sparkle has returned. She is now enjoying a pampered garage life in the big city and gets out a couple times a week (when it isn't raining). Now, if we can ever get all those damn acorns out of her ac blower fans she will be really cool.

LOL - thanks for the update :)