99 jeep grand cherokee brake lights do not work

have you check for power at the sockets for the brake light. if you have no power and as you say the brake light switch is good then you have a brake in the wire between the two that you will have to find and repair.

Generally, the break light switch is located top back side brake pedal; also check in THIS DIAGRAM position 23 for Brake Switch fuse.

Hope helps.

i think your switch in the door has just decided to pack up at the same time as you were working on the vehicle and its just coincidence or murphys law as we call it in the trade

first check fuse, then check bulbs if not either of those then bad brake switch, which is located at the top of the brake pedal. I'm sure you're reading this thinking ok **** I know it's not the bulbs......I have a 99 that had no brake lights at all. Like a **** I didn't check the bulbs til last thing what's the odds of all 3 bulbs blowing at the same time. They were though, all 3 blown.

I would suggest that you take a look here (I used this to correct brake-light issues on my '01):

http://www.topix.com/forum/autos/jeep-grand-cherokee/T63DRCOTUFKMHQ207

Many Grand Cherokees have had this type of issue. The thread is lengthy, but does cover just about every type of issue known with the tail/brake lights.

Well. The rear brake light go out is a command problem for the 99-04 Jeep WJ. I personally think there is a short somewhere from the factory design.

Sounds like your brake light switch needs to be replaced.  It is attached to the brake pedal and should cost you around $20 from an auto parts store.  If the fuses and bulbs are good there is a 99% chance it is the brake light switch.  Hope this helps!  Thanks for an honest rating and for using FixYa.

You can adjust the switch by putting your thumbs on either side of the switch plunger and pushing toward the brake lever. The switch shaft will ratchet into the new position which is will then be depressed by the brake lever when it is the brake is not being depressed.

i take it the brake lights work ok when the lights are not on??? check the ground going to the lights