the brakes are wired into the turn signal assembly. i had the same problem with my car the middle rear light would light up but not the left or right. if you wedge something in the turn signal you will notice your lights work. there actually was a recall on that part.the switch is actually on the brakes that's what makes them light up when you press it. if the wedge doesn't work then you will have to replace the whole turn signal switch located in steering collum. hope this helps
Changing the brake light switch in your Chevrolet Monte Carlo is quite simple. The brake light switch simply plugs in and out.
On a 2003 Chevrolet Monte Carlo, the brake light switch is located above the brake pedal, mounted on the brake pedal assembly. To access it, you may need to remove the lower dashboard cover. The switch is typically a small, cylindrical component that activates the brake lights when the pedal is pressed.
Brake light switch on the brake pedal is defective
If the bulbs are good then the brake light switch is bad, it's on top of the brake pedal up under the dash.
* It could be a blown fuse or * the brake light switch on top of the brake pedal under the dash is bad or * the turn signal switch is bad.
The brake light switch is bad, look on top of the brake pedal under the dash and you will see the switch, replace it and you will have brake lights.
check fuses first and if good more than likely the brake light switch is bad and that is on top of the brake pedal up under the dash.
It should be in the fusebox with the rest of the fuses.
check your break fluid.
carefully
Rear loom ground not contacting. Bulbs burned out or missing. Brake light switch or connection to it is fubared.
Very possible a door switch is defective.