Owners or dealers may have installed fog lights on the vast majority of cars. Though a nifty addition to make a car look all the more stylish, it is nevertheless a safe addition requiring only minimal attention. It is essential to keep the beams properly aimed. This is especially true with fog lights, which should light the road and not the trees. In fact, many states require fogs only to work with low beams. In most fog lights which have their own mounting, first undo the screw in the vertical housing on both sides of the fog light lens and take out the retainer(s). Remove the glass lens assembly from the mount carefully. There are wires at the back you need to take note of. Unplug the wires from the lamp and the ground connector; both wires may have the same connector, with labels so that fuses do not blow on reassembly. At the rear of the lens, depress the ends of the spring clip to expand it away from its holder and swing it to one side. Remove the bulb from the reflector and fit the new one in ensuring that the square notch in the bulb flange fits over the guide on the reflector, then swing the spring clip over the bulb. Reattach the wiring to the ground and the bulb, place the reflector assembly in the plastic housing, and mount the frame pieces. Lastly, install your screws and tighten them enough to hold, if you clamp them too hard the lens will crack.