i here that the grands have problems with the brake lights not working. if i have my lights on, my 3rd light stays on with the tail lights, and when i put the brakes on the tail lights go out and all that's on is the 3rd light (brighter of course). i've replaced the bulbs even though they were still good and still no brake lights. they work fine without the headlights on. i'm stumped, the only thing i can think of is a bad wire somewhere. oh and i checked the fuse box in the cab and they were ok. i reeeaaaally don't feel like getting pulled over because of a damn light bulb.

 

It could be a possible ground problem or the wrong bulbs in general...when you pull out the lens look around for bare wires or any sign of ELECTRICAL TAPE....lol i know it sounds weird but thats a big sign of home mechanics like myself and many others...good luck

 

You don't say what year your jeep is.But you maybe getting a feed back from the wrong biulbs or the rear tail lamp assy are shorted on the circuit board.

 

that's happened to me to! it was the switch.