my back brake lights don't work, but the brake light on the back door does what could be wrong
depends on the vehicle, some yes some no
A few posibilities are. the bulbs have blown, although the side and brake light bulbs are the same bulb, they use separate filiments, The fuse has blown or the brake light switch is faulty.
It may be a fuse.
the bulb has 2 filaments. One may not be working. Try replacing the bulbs. Or, there is a bare section on the wires that lead to the bulb.
Since most brake/turn use the same filament in the bulb(1157) then if the turn signal switch is bad or offset then it will effect the brake lights.
Many cars use the same bulb for the brake and turn indicator. Seems like one is burnt out. Have someone step on the brake and see if one of the brake lights does not respond.
If you have the same bulb for brake and signal, brake light power needs to be interrupted by the signal lights, The brake circuit has to go through the signal light switch so the problem could be there.
Could be a bad bulb. The same bulb has two filaments, one for the tail lights and one for the brake lights.
Almost all cars use a bulb with two element in it. One for the tail light and one for the brake. It's rare for them to both burn out at the same time.
check the light bulb same double element bulb for both lights
The marker lights and brake lights run on two different circuits, and usually light up two different filaments on the bulb. If both tail lights are out, either a fuse is blown, a wire is compromised, or both marker light filaments on the bulbs are broken.
In 1984 Corolla sedan and coupe the brake lights are mounted in the trunk lid. Just grip the socket and turn counter clockwise 1/4 turn and the bulb and socket will come out, grasp bulb and another 1/4 turn bulb will come out. Sylvania Part № 7443LL 2 filament bulb (same bulb is tail lights)