A fog light (or “fog lamp”) is a light housed at the front of a vehicle near the ground with the intention of providing visibility in foggy conditions. Modern vehicles feature a pair of fog lights.
The light from your headlights tends to reflect off of moisture in the air. Although a clean set of headlight lenses and bright bulbs will allow you to see for a good distance, in the fog they can actually decrease visibility. Fog lights, on the other hand, have a wider beam and are aimed toward the ground where they shine beneath the fog rather than straight into it. This lessens the reflected light and affords a higher level of visibility.
Due to their proximity to the ground and susceptibility to debris from the road, fog light assemblies tend to become damaged, in some cases, more than other vehicle lights. That said, if one of your fog lamps is not working, the likely problem is a burned out fog light bulb. You might notice that the light is inoperative by simply walking near the front of your vehicle. You might also notice that the lighting at night does not appear to be evenly cast in front of the vehicle, indicating that a light has failed. Some vehicles might include a dashboard warning light to signal when a bulb is bad.
To replace a fog light bulb, a technician will need to gain access to the back of the fog light assembly mounted (in most cases) in the lower part of the front bumper of your vehicle. This might be done from the front of the bumper. But, in most cases, the technician will need to remove a fender shield or lower bumper shield to get at the assembly.
From there, the wiring connector must be unplugged from the bulb, and the bulb retainer must be removed from the assembly. Once the old fog light bulb has been extracted, the new bulb is inserted into place, the retainer applied, and the harness plugged back in. The shields are reinstalled and the light is aimed and tested.
It should be noted that the technician must avoid touching the new fog light bulb with bare hands. Otherwise, the life of the bulb might be significantly shortened.
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