Trying to get brake lights going. No luck. Had it 2 weeks and just now getting to this. Fuse is good. I have power at switch and when pedal is engaged I have power on other side of switch. Also put in new bulbs. Parking light works on bulb also. Any help would be highly appreciated. Thanks

I just went through this last week with trailer lights, turned out the ground wire wasn't hooked up.

What year is this Jeep?

Duplicate post.

88....but the parking lights work. Only thing in whole assembly that doesnt work is brake lights.

Check and see if there is power to the bulb, might have a nicked wire (and if it's far enough forward it would cause both lights to not work). Doesn't sound like a grounding issue, therefore that's the only thing it could be. Might check and make sure the ground wire is tied into chassis ground just to be sure.

I just thought. I havent investigated near the hitch. There isnt a visble pigtail but who knows. These 2 weeks ive had this thing has been full of surprises.

Look at the brake light switch at the pivot point of the brake pedal?

Its hot on both sides when pressed. I thought maybe these were notorious for having a bad socket or something. Ima hafta dig deep on the issue. Im ready to drive it.

Do you have a trailer readily available (or those little magnetic tow lights)? Hook it up and see if the brake function works. That will give you a better clue of where to look. If the brake function on the trailer works, wherever the wiring in the XJ wiring harness to take the system from a 4 wire to 3 wire for the trailer, there will be a problem aft of that. If no brake on the trailer lights, then the problem is in front of it.

The 4 wire to 3 wire is a harness with 3 relays located behind the spare tire.

Did you ever solve this? I am going through the same thing. Replaced brake switch, ran through my harness and everything is good. Replacing all bulbs even though they look good tonight. Fuses good. I'll be going through with a voltmeter tonight too. Driving me nuts and it's getting ready to snow here.