There's a ground in the back area too. Really obvious.

I checked my PDC and didn't see a blown fuse. Which rubber boot were you referring to? I have one on each top corner. Would I just remove those and look for faults in the wires?

And the ground seems to be fine, but would that mess with all three of my brake lights?

Sounds like there's some differences between the '99s and '94s. Mine has just one rubber tube running from the body to the hatch, right in the center. But yeah, there could be faults in there. The wires for the third brake light, wiper, and defroster run through those.

They are probably all interconnected.

Mine has rubber boots on either side and wires attached to the window on both side that lead up to them. I took my hatch third brake light out and checked all the wires that were there. I couldnt find a PDC diagram for my jeep but I checked all the fuses there and nothing was blown.

I'm stumped.

Again... start by taking off your spare and pulling that plastic wall off...

Check at the junction that has all your wires if your brake wires are hit to that point when the brake is applied. ...

At least you can narrow down if the problem is in the front or back of your jeep. If you're hot to that point, we'll have a better idea where to direct you.

Again, buy a can of electronic cleaner before you pull it all apart. Get new batteries for your voltmeter also.

I'm sure there are many wiring diagrams listed to tell you which color wires to check... or maybe someone will chime in on this one with the colors.

Did you ever happen to fix this? Just picked up a 94 xj and am in the same predicament

Right above the member's name is the date of their post.
FYI, this last post is nearly 8 years old.