Backup Lamp Switch Function

If the switch is functioning normally a circuit is completed when the switch is triggered and the white lights in the tail lights will illuminate.

Backup lamp switch function.

If the contacts in the switch are worn or have failed then this may cause the lights to function intermittently. In combined function installations the lamps produce brighter red light for the stop lamp function and dimmer red light for the rear position lamp function. In the on position the switch allows current to flow from the pink wire this is the 12 volt power source to the backup lights when the gear selector is placed in reverse. After putting the transmission in reverse unplug the electrical connector attached to it and check it using a test light.

A backup light switch screws into the transmission and is triggered when you shift the vehicle into reverse. You could have the gear set to drive or reverse and still be able to crank it. If you have an automatic transmission the transmission range sensor handles the function of the backup lights in lieu of a switch. There is no adjustment for the backup light switch and no way to repair it.

If it s bad replace it. If the lamp lights up this means that there is no problem with the battery supply. Now reattach the switch to the connector and check the connector again with the test light. If the engine is running you will be able to crank it again too.

Replacing a backup light switch is fairly straightforward if you know what the switch looks like and where to locate it on your vehicle. The backup light switch is similar in that it is also an on off switch. Reverse lights function intermittently. Regulations worldwide stipulate minimum intensity ratios between the bright stop and dim rear position modes so that a vehicle displaying rear position lamps will not be mistakenly interpreted as showing stop lamps and vice versa.

Intermittent functionality of the reverse lights is a symptom that the backup light switch may be having a problem.