If they are *not* working, the problem could be in several places:
* Brake light switch: This is the most common culprit. It's a relatively inexpensive and easy part to replace.
* Bulbs: Burnt-out brake light bulbs are also a frequent cause.
* Wiring: Worn, damaged, or corroded wiring between the switch and the lights can interrupt the circuit.
* Fuses: A blown fuse in the system will prevent the lights from working.
* Brake light relay (if applicable): Some vehicles use a relay, although it's less common for the brake lights themselves.
* Tail light assemblies: Issues within the tail light assemblies themselves, such as a short circuit.
To diagnose the problem, you should first check the simplest things—the bulbs and fuses. If those are fine, you'll need to test the brake light switch and then start tracing the wiring.
