2002 XKR no issues ,runs beautiful.........went for a two hour cruise,came home and shut it down.
Went back to retrieve something out of the trunk and everything had shut down.No power to anything.No interior lights when you open the door and remote will not unlock the trunk.Even the horn will not blow.
When I trigger the remote lock button,a red light blinks next to the park indicator and the remote "unlock" button turns it off but nothing happens.
Thought I'd accidentally triggered the valet function but that won't work either.
Might be a case of driver stupidity but I'm stumped.

 

It's unlikely the battery has flattened that fast after a long drive.

One possibility is a loose or broken cable from the battery to the main junction box in the luggage compartment (this is a 2005 XK8 but your 2002 is similar):



Can you open the luggage compartment with the key to check this?

Graham

 

Got in the trunk and checked....there are two connectors that are not in use....might be for diagnostics?Photo Booth Library.zip
oops....might have accidentally sent a large file.Took a picture of wiring but I'm borrowing my wife's Apple and I'm not an Apple guy