Hello and welcome to JustAnswer!
The brake light and turn signal use the same bulb. Try swapping out the brake/turn bulb with a new one or one from the other side of the Jeep and see if it works. If it doesn't work then you either have a problem with wiring on the Jeep or there is a problem with the circuit board between the electrical connector and the bulb itself. We can get it figured out if we need to if you have a voltmeter or test light to do some testing.
Both turn signals are working. I will have to get a test light and check connector to the tailight housing right?
Ok, if neither brake light works that's a completely different issue. I thought you had one light not working. Be sure that you've checked fuses in both panels, the one under the hood and the one in the dash. If the fuses are good then we'd definitely need a test light to continue and come to a sure conclusion, but you may need a brake light switch. This is located on the pedal bracket assembly above the pedals. It has a plunger that contacts the pedal that opens and closes the switch contacts as you press and release the brake. The thrid brake light is on a seperate circuit from the other two brake lights, the reason it can work and not the others. If you've got a test light we can test the brake switch before you replace it.
I checked the switch and it is working fine. but still no break lights? what is next.
Pull either one of the rear lamp housings, find the white/tan wire there and see if it powers up when you press the brake.