The backup light switch is the electronic switch on a vehicle that is responsible for activating the vehicle’s reverse lights. The switches work by activating the lights when the transmission is put into reverse gear. In some vehicles, such as large trucks or vans, the backup light switch may also activate the backup alarm, which beeps to notify pedestrians and other drivers that the vehicle is traveling in reverse. Backup lights are an important safety feature installed on all vehicles to promote safety and prevent accidents. When the switch that activates them fails, this safety feature is disabled and the vehicle may be more susceptible to accidents. When the switch does fail, usually a few symptoms will be produced that can alert the driver that a problem has occurred and should be serviced.
1. Reverse lights function intermittently
Intermittent functionality of the reverse lights is a symptom that the backup light switch may be having a problem. If the contacts in the switch are worn or have failed, then this may cause the lights to function intermittently. You may notice that the reverse lights will come on sometimes and not others, or that they may flicker on and off rapidly or randomly.
2. Reverse lights stay on at all times
Another symptom of a failed backup light switch are reverse lights that are on at all times. If the switch shorts internally, this may cause the lights to stay on permanently. This will not only be a problem in that it will make the vehicle appear that it is in reverse gear when it is not, but it will also cause the bulbs to burn out much more rapidly than they normally would.
3. Reverse lights fail to come on at all
The most obvious symptom that the backup switch has failed are reverse lights that fail to come on at all. The backup light switch is what directly controls the lights, so if it fails, then the lights will cease to function. This will leave the vehicle without a visual cue to notify pedestrians and other drivers on the road that the vehicle is traveling in reverse, which is unsafe.
Because reverse lights are an important safety feature that is mandatory on all road going vehicles, if the backup switch fails, this important safety feature will be disabled. For this reason, if you suspect that your vehicle’s backup light switch is having a problem, have a professional technician, such as one from YourMechanic, diagnose the vehicle’s lights to determine what the best course of action may be. If needed, they will be able to replace your backup light switch for you.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Backup Light Switch and was authored by Ed Ruelas.