My right rear brake light is not working!! The driving lights work fine. It's not the socket. I removed the short harness and tested at the plug behind the back right rear panel. At this plug everything works except the brake light when I depress the pedal. The left rear works just fine.

Suggestions on what to check?

change the bulb.

Step 1: Fill out the info on your rig. Cherokees were produced for a decade-and-a-half and, believe it or not, they aren't all the same.

If it doesn't work at the harness, it's not gonna work at the bulb no matter how many times you change it. On mine ('89), the right side tail light crosses over the roof and connects to the harness behind the rear quarter on the driver's side. I was having the same problem Smalley was and traced it to a botched trailer light wiring job at the harness behind that driver's side rear panel.

Ultimately, you'll have to use a test light or a multi-meter to trace it back in the direction of the brake light switch (under dash), there can be many causes... you'll probably know when you find it

In a previous post she said she has a 94 XJ 2 door.

94 two door, 4.5" RC short arm X Flex, 33" x 12.50" x 15" Mud Kings, 4.0L, AW4/NP231

I did change the bulb. on the original bulb the glass was loos from the metal so I replaced the blub and still no workie. Sounds like I am going to have to do some tracing back

OP never said they changed the bulb. couple that with mis reading the OPs post, it would make sense for the bulb.

She ("she" according to CCKen) stated in her OP that she tested at the harness plug and there was no power to the socket. I do, however, agree that the first step should always be to replace the bulb but in this case, it appears the problem lies elsewhere.

Smalley, I believe both brake lights are fed from the driver's side rear quarter panel harness rather than each being a home-run lead all the way to the fuse panel/brake switch so you should begin your search at the harness connector behind your spare tire mount. That should limit the headache because you're only going from there to the other side of the hatch rather than from all the way up front.

Sorry, that wasn't super clear. There is a single lead [I believe] from the brake switch to that rear quarter panel harness plug (behind spare tire mount) and from there it splits off, one lead to driver's side brake light, one to passenger side. If one light is working and the other isn't then your problem lies somewhere between that harness connection and the dead socket.

Check the plug contacts for corrosion and water damage, clean if necessary, apply dielectric grease to plug contacts before re-connecting. Check for bad splices and botched PO MacGyvering.