The fog light switch is the electrical switch that is responsible for controlling the operation of the fog lights. Fog lights are additional lights that are located beneath the headlights. They are designed to provide additional visibility during adverse weather conditions, such as heavy rain or dense fog. Their low placement and wide angle helps the driver keep sight of the edges of the road, as well as the lanes. When the fog light switch fails, it can leave the vehicle without functioning fog lights. Usually a bad or failing fog light switch will produce a few symptoms that can alert the driver of a potential issue.
1. Fog lights do not turn on
One of the first symptoms that is commonly associated with a bad or failing fog light switch are fog lights that do not turn on. For vehicles that do not utilize automatic fog lights, the fog light switch is the switch that is responsible for turning the fog lights on and off. It operates the same as any other electrical switch, and can break or have internal failures that will render them inoperable. A broken or failing fog light switch will leave the fog lights inoperable, even if the bulbs are fine.
2. Fog lights are dim or flickering
Another common symptom of a problem with the vehicle’s fog light switch are fog lights that are dim or flickering. If the switch has any sort of internal issues that prevent it from properly supplying power to the fog lights, then it may cause them to illuminate dimly or even flicker. This can also be caused by a problem with the fog light bulbs, so a proper diagnosis is highly recommended.
3. Blown fog light fuse
Another symptom of a possible problem with the fog light switch is a blown fog light fuse. If there is any sort of issue with the fog light switch that allows an excessive amount of power through the circuit, such as a short or power surge it can cause the fuse to blow, which will disable the fog lights. Power can be reactivated by replacing the fuse, however the fuse may blow again if the original problem that caused it to blow in the first place is left unattended.
While fog lights are not normally used during regular driving conditions, they can be a very useful tool for increasing visibility and therefore safety during adverse weather conditions. If you suspect that your fog light switch may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if your car will need a fog light switch replacement.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Fog Light Switch and was authored by Eduardo Ruelas.