* Reverse Switch: A switch is located on the transmission. When the gear selector is moved to the reverse position, this switch closes, completing the electrical circuit.
* Wiring Harness: Wires run from the reverse switch, through the vehicle's wiring harness, to the backup lights.
* Backup Lights: The lights themselves are simple incandescent bulbs (or possibly halogen in later model years), which illuminate when the circuit is complete and electricity flows through them.
* Fuse: A fuse protects the circuit from overloads. If the circuit is overloaded (e.g., a short circuit), the fuse blows, preventing damage to the wiring or other components.
* Ground: The circuit also requires a good ground connection for the electricity to flow back to the battery.
If your backup lights aren't working, the problem could lie in any part of this system: a faulty reverse switch, a broken wire in the harness, a blown fuse, burned-out bulbs, a poor ground connection, or even a problem with the vehicle's electrical system itself.
