a fan of Occam's Razor I see. That space is very tight, the wires are packed together. I was hoping there might be a sub-harness which would be smart engineering. I guess I could pull new wire thru the kick panel.

 

It is a sub-harness. You'll need to pull the kick panel and door card anyway to replace the harness. Yes, you can scour the salvage yards and eBay for a replacement. It will have to match your current harness. Once you have the harness out, you can rejoin the broken ends and inspect the other wires. You may have to splice in a small extension of wire. You may even consider using a longer splice wire so the splices themselves are on opposite sides of the passage from the body to the door and no longer inside the boot.

You can find the FSM and parts manual for download here: https://archive.org/details/addition...y=xj+jeep+2001

(You can remove the "2001" from the string to find other years if needed).