While driving my 2000 XJ, the brake warning light appeared on my dash (accompanied by a slight thud).
I drove home the remaining 5 miles and did not feel a difference in the feel of the brakes. The brake warning light remains on when I turn off and restart the vehicle.

Additional background:

• Brake lines were replaced last year (5,000 miles ago)
• Rear brakes were done 20,000 miles ago
• Front brake rotors/pads were replaced 6,000 miles ago
• Brake pedal makes "whooshing" sound when I press down and has always felt relatively soft (even before warning light came on)

Action# 1: Once parked, I pulled the parking brake handle up and down to make sure it was fully seated (seemed fine).

Action#2: When I got home, I checked the brake reservoir from the master cylinder and noticed it was empty. I topped it off with DOT 3 brake fluid and pumped my brakes several times to see I could identify where the leak was coming from. I inspected the brake booster by disconnecting the vacuum hose and using a zip tie to see if there was any fluids inside the brake booster (it was dry). There was no fluid appearing on the outside of the brake booster and I inspected the back of all four wheels and did not notice any wetness on either wheel or on the ground. While inspecting the wheels, I did notice a crack in the parking brake cable (see pic below).




Any thoughts?

 

Bleed the system and test for leaks.

 

To add a bit to the above post.

Tha brake fluid went somewhere, and the thud you heard may have been the piston in the proportioning valve that triggers the light.
There's probably a leak somewhere, given what you've done so far probably in a line. Rather than going through the hassle of bleeding things now, save that for later, I would fill up the fluid, park on a nice clean dry surface, start it and pump the brakes hard for a while. Look for the puddle.

The parking brake boot hole shouldn't be the cause of the problem

When you fix the leak you'll need to reset the light/piston , usually by stomping on the brakes really hard.

 

Thanks - I tried this approach again with a flashlight and was able to see brake fluid coming out the back of the rear drivers side wheel. It looks like it was the brake cylinder that was the culprit.

 

When you stomp on the pedal to reset the light...the truck must be running or it will not work