2002 XK8 Convertible: Been sitting in the garage for about 1 month. Yesterday when trying to start nothing but a single click and multiple message center indications scroll; doesn't even turn over. The click almost sounds like some sort of arcing or short. Today I go out to see if I can troubleshoot and only the faintest of click - almost inaudible. Also the message center lights are so dim as to not be readable. Drivers window went down part way when the door was opened and not even enough juice to put it back up; also the winshield wipers tried to operate on their own. Apparently overnight things have changed maybe draining the battery; new battery just installed last year. I thought of trying to jump the battery, opened the trunk (with key) and the trunk lights flash on & off. Wondering about a short and possibly causing more damage if I try to jump battery, I quit and decided to see if anyone has any suggestions before proceeding. I'm at a loss as to where to even begin diagnostics beyond checking battery voltage.

 

Your battery is drained. Recharge it.
Expect assorted strange errors when you restart the car. You might have to do a "hard reset".

There are multiple threads about low battery problems and how to solve them. The best is to add a trickle charger to prevent it from draining in the first place.

Cheers
Bill

 

+1. Charge the battery, do not jump it, then disconnect a terminal for a minute or so and reconnect it.

Jumping it in this state might actually damage the electronics.

 

If you haven't charged it already, disconnect the battery first. Reconnect when the charge is done.