Automotive fog lights are an indispensable safety feature for those who live in areas prone to early morning fog. Wiring an after-market fog light kit requires a basic understanding of electrical wiring, safety and the proper tools. Doing the job yourself will save you the cost of having an automotive shop do it for you.
Locate a place on the front bumper where you are going to install your auto fog lights. Usually, this will be low to the ground. If possible, the location should be one that will allow the mounting bolts to come in contact with the frame of the vehicle for better grounding.
Mount the lights to the bumper or frame using the hardware supplied in the after-market kit. This will usually consist of self-tapping mounting screws or a system with a bolt, washer and locking nut. If self-tapping screws are not supplied, you will need to use the drill and an appropriately sized bit to drill mounting holes for the bolt to go through.
Disconnect the negative battery terminal on the car battery before attempting to connect any wiring. This safety step will prevent possible sparks that can ignite fumes from various sources on the automobile. It also prevents you from accidentally shorting out the battery.
Route the wiring from the fog lights through the car's firewall to the dash inside the car. The wiring will go through the supplied two-way switch before being routed to the battery for connection to the power source. Be sure to avoid any moving parts under the hood. It is best to follow already-installed wiring harnesses and secure the wire every few feet with zip ties or electrical tape.
Locate a spot on the dash where you will mount the fog light switch. Install the switch with the hardware provided in the kit.
Connect the wire running from the lights to the switch. Run the rest of the wire from the opposite side of the switch to the battery's positive cable. This will ensure you have power to the switch. Alternately, the power can also be derived from the fuse box under the dash. This alternate method is sometimes preferred because it will automatically shut off the lights when the ignition is turned off, thus preventing accidental drain on the battery.
Ensure that the auto fog lights are properly grounded on the front of the vehicle. If the mount is not connected directly to a part of the frame, then you will need to run the ground wire supplied to a self-tapping screw and washer onto a location on the frame. Most bumpers are mounted directly to the framework at two or more points on either side of the radiator. Look for these contact points, and mount the grounding wires there if applicable.
Reconnect the car's negative battery cable, and test the lights for proper working condition. If any adjustments need to be made or any loose connections are found, always be sure to disconnect the negative battery cable before working on the wiring.
