US-market versions of European cars may or may not have wiring for the rear fog lights and some with integrated rear fogs (Mercedes W126 for example) may or may not have a socket so all you need to do is add a bulb. If you don't have a socket or wiring you will need to add them. Many cars (even including such high-end makes as Porsche and BMW) have over the years used separate rear fog units mounted below or in the rear bumper. Some cars, such as W111 Mercedes shown above, make a "pair" out of one rear fog and one reversing (backup) light. This is also a fairly common arrangement where the rear fog is integrated into the taillamp clusters -- the driver's side cluster has a rear fog, and the passenger side cluster has a reversing lamp. Examples include late Saab 9000s, the European versions of the Chrysler Vision and Chrysler LeBaron, certain Audis, etc.
This method gives you fuse protected rear foglights with the factory dash indicator without going thru the light control module in the electronics box under the hood.
You must solder the switched + for the foglight switch to the rear foglamp indicator bulb contact on the bulb itself. Use a meter to see which side of the circuit board on back of instrument panel is grounded, wire goes to opposite side on bulb (if it's wrong 2a fuse will blow)
Rear foglight socket must be cut out and cleaned up with xacto knife and or small file so that backup light socket will fit in. Follow the pattern you see on the plastic plug. The contacts for the bulbs can be made from old speednuts or other material that you can solder wires to, look at the other conectors for pattern.
Since I had the steering column out and the battery disconnected, I decided to pull the cluster and find which pin was the one for the rear fog indicator light with my multimeter. It is in the long connector on the left side.
|Rear Fog lights off||Rear fog lights on|