1999 jeep grand cherokee brake lights

I have a 2004 Jeep Grand Cherokee that I purchased only three months ago. It has already been in the shop three times in a month so I fee like I can help you with your problem. My rear brake light did the same thing and I just had to purchase the whole light socket. It only cost $13.00 from Jeep. I know your jeep is a 99' but the mechanic said that all Grand Cherokees from the last six years or so had the same problem. Changing the light bulb won't work. It will simply burn your bulb out. Simply buy the plastic socket that the bulb snaps in and that should fix your problem. It did for me.

N Grand Cherokees the brake lights are known for having it's contacts get dirty/rusty.If you have bought new bulbs and they still wont work, then you just need to disconnect the light, take out the light seat, and scrub it with CLR and a medium tooth brush. When you reinsert the bulb please be sure that the bulb lines up with the seat contacts.
Problem permanently solved!!!

The light is shorted on the inside. The circuit has shorted and if you have tried replacing all the bulbs then your only other option is to replace the whole light assembly itself. Wouldnt suggest going to the dealership for the taillight but you can find a whole lot cheaper online. Plus it takes like five minutes to replace yourself. So whatya got to lose!