this sounds like a fuse or 2. that's where i would start.
check your fuses
It should say TAIL for taillights or maybe brake lights.
They aren't. The brake light circuit is not connected with the headlight circuit.
replace the lamp socket they short in a strange way, it happened to me 3x. the socket carbonized from bulb heat
brake relay or sensor
my fuse panel (with the descriptions) is gone off of my 2000 jeep grand Cherokee Laredo, how to i get a description of what all 32 fuses control on my jeep?
Yes. They work fine if the lights are off (ie. during the daytime) but when the lights are on all the brake lights are off. Our Grand Cherokee has tons of problems. The ac sometimes does not work, the gauges go crazy, the power windows play dead sometimes. We got it checked out. Mechanic says our body control module is going bad.
i fixed this problem by replacing the brake light switch that seemed to be working fine otherwise.. in a a fit of rage in frustration i shattered the old one off the pedal and had to buy a new one, magically now my lights work.
How to change the brake switch on a 2004 Jeep grand Cherokee Laredo
Check the bulbs in case they have fused, next check the fuse, and finally it could be the brake light switch which may need replacing
You need to check the wiring for power to the bulbs.
The emergency or parking brake on 2003 Jeep Grand Cherokee operates a set of brake shoes inside a hub on the rear axles, this is incorporated into the disc brake setup.