GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Fog Lamps



See Figure 1

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Fig. Fig. 1: Common fog lamp mounting

Most fog lamp bulbs are easily replaced by removing the lens cover (standard bulbs) or lens trim panels (halogen bulbs) for access. Most later model vehicles are equipped with Halogen bulbs which require extra care. Handling a Halogen bulb improperly could cause it to shatter into flying glass fragments. To help avoid personal injury follow the precautions closely. Whenever handling Halogen bulb ALWAYS follow these precautions:

Turn the lamp switch OFF and allow the bulb to cool before changing it. Leave the switch OFF until the change is complete.
ALWAYS wear eye protection when changing a Halogen bulb.
DO NOT drop or scratch the bulb. Keep moisture away.
Place the use bulb in the new bulb's carton and dispose of it properly.

  1. Disconnect the negative battery cable.
  3. Remove the lens trim panel screws from the front of the lamp, then pull the lamp and lens assembly forward from the case and turn it over.
  5. Unplug the white wire connector inside the braided insulator (leave the ground wire connected). Note the position of the wire clip at the lamp and lens assembly, then squeeze the edges of the clip together and remove it.
  7. Lift out the wire and the halogen bulb assembly.

To install:
  1. Install the white wire connector to the wiring in the brained insulator.
  3. Install the bulb into the back of the lamp and lens assembly.
  5. Install the wire clip to hold the bulb in place. Make sure the clip is firmly in position and the bulb is not loose.
  7. Install the lens and lamp assembly into the case, then secure the trim panels using the retaining screws.
  9. Connect the negative battery cable and check for proper operation.


Before installing any aftermarket light, make sure it is legal for road use. Most acceptable lights will have a DOT approval number. Also check your local and regional inspection regulations. In certain areas, aftermarket lights must be installed in a particular manner or they may not be legal for inspection.

  1. Disconnect the negative battery cable.
  3. Unpack the contents of the light kit purchased. Place the contents in an open space where you can easily retrieve a piece if needed.
  5. Choose a location for the lights. If you are installing fog lights, below the bumper and apart from each other is desirable. Most fog lights are mounted below or very close to the headlights. If you are installing driving lights, above the bumper and close together is desirable. Most driving lights are mounted between the headlights.
  7. Drill the needed hole(s) to mount the light. Install the light, and secure using the supplied retainer nut and washer. Tighten the light mounting hardware, but not the light adjustment nut or bolt.
  9. Install the relay that came with the light kit in the engine compartment, in a rigid area, like a fender. Always install the relay with the terminals facing down. This will prevent water from entering the relay assembly.
  11. Using the wire supplied, locate the ground terminal, or terminal with the number 85 next to it on the relay, and connect a length of wire from this terminal to a good ground source. You can drill a hole and screw this wire to an inside piece of metal; just scrape the paint away from the hole to ensure a good connection.
  13. Locate the light terminal, or terminal with the number 87 next to it on the relay; and attach a length of wire between this terminal and the fog/driving lamps.
  15. Locate the ignition terminal, or terminal with the number 86 next to it on the relay, and connect a length of wire between this terminal and the light switch.
  17. Find a suitable mounting location for the light switch and install. Some examples of mounting areas are a location close to the main light switch, auxiliary light position in the dash panel, if equipped, or in the center of the dash panel.
  19. Depending on local and regional regulations, the other end of the switch can be connected to a constant power source like the battery, an ignition opening in the fuse panel, or a parking or headlight wire.
  21. Locate the power terminal, or terminal with the No. 30 next to it on the relay, and connect a wire with a fuse of at least 10 amperes in it between the terminal and the battery.
  23. With all the wires connected and tied up neatly, connect the negative battery cable.
  25. Turn the lights ON and adjust the light pattern if needed.