Written by Mike | Credit to Eric Stevenson

INTRODUCTION
I have compiled this DIY based on several others I’ve seen online. I respect all work done by other enthusiasts and will credit them where necessary. The pictures and tips I am using came from Eric Stevenson’s DIY and I also used some tips provided by dzcad. This DIY describes hooking up a rear fog into a US-spec Jetta taillight. I plan to replace the photos used in this DIY once I do this install in my own Mk3.

PARTS NEEDED

• Euroswitch
• OEM repair wire, includes two connectors, VW P/N 000-979-133-A
• 16ga wire (20 ft)
• 21W bulb
• soldering iron
• heat shrink tubing
• zip ties

THE SWITCH
Remove the ABS panel using your flat head.

Now you can remove the euro switch. There is a plastic catch that needs to be pushed in for removal.

Basically, you’re running a wire from slot 12 on the headlight switch harness to the driver’s side taillight.

Cut the repair wire (VW P/N 000-979-133-A) in half, leaving two pieces with a female connector on one end and bare wire on the other. Connect one of the wiring connectors to the end of your 16ga wire (crimp or solder). It’s a good idea to shrink wrap where you solder, or at least use electrical tape to cover it. Insert your wire with the new connector into the headlight harness, pin 12.

Next you’ll be running that wire all the way back to the taillight.

RUNNING THE WIRE
You’ll probably want to hide your new rear fog wire. The factory wiring is hidden by body panels and carpet throughout the car. There is a harness that runs from behind the dash to the driver’s side taillight. It passes under the driver’s side door sill and up under the back seat.

From the back of the headlight switch, the wire runs down past the fuse box and behind a panel. Working under the dash is fairly difficult and there are only a few places to secure the new wire.

Look at the dead pedal. To the left is a panel where the hood release is located. There is a screw on that panel that needs to be removed. You can run the new wire behind that panel and on to the door sill.

There is one screw on the door sill that needs to be removed. It is located next to or behind the driver’s seat. If you follow the seatbelt down to it’s lower mounting bracket, you’ll find it. Unscrew the screw with a phillips head screw driver and then pull it out.

To remove the door sill you need to grab underneath it and pull toward the center of the car. The door sill has a lower lip on it; you need to free the lip. Once free, it should pull straight up. Run your wire alongside the others until you meet the rear seat. At the rear seat your wire will take a small detour, but don’t worry, he’ll meet up with his friends later.

Next you want to remove the three screws that hold the rear door panel in place. This allows you to move the panel a little so you can shove the new wire under the carpet.

After the three screws are removed, lift the rear seat forward and expose a cap. This cap, as well as the visible cap below it, need to be removed. The lower cap screws on, the upper is pressed in. Just pry it up. Now the wire detours from his friends.

You can follow the stock wiring harness again when you get to the rear seat back. The stock harness goes through the metal base of the rear seat. You don’t have to fish the wire up under there though, just make sure it gets to where it needs to go.

Run the wire under the rear seat back and through the trunk area. You’ll need to move the trunk carpet out of the way.

If all went as planned, you will have arrived at the driver’s side taillight with your wire.

HOOKING UP THE FOG
Connect the remaining half of your repair wire (VW P/N 000-979-133-A) to the 16ga wire you just routed. Then insert it into the only open pin on the left inner bulbholder.

You will need to Dremel out the plastic plug where the bulb goes. The DOT spec taillights are the same as E-Code taillights, but DOT spec taillights do not have the rear fog plug knocked out. It should be clearly defined and easily removed with the taillight still in the car.

Insert your 21W bulb into the bulbholder and put it back into the taillight. Now you are finished! And remember, the true Euro setup for rear fogs is to have one only on the driver’s side. Also, please don’t drive around with your rear fog on all the time. It is only meant to be used when it is foggy.