View Full Version : B5 A4: Fog Light HID Conversion

09-14-2008, 08:11 AM
Tools Needed:
Phillips Head Screwdriver
1” Hole Saw
1/8” Drill Bit (for optional pilot hole)
High Temp RTV Silicone
Zip Ties (included)
Torx T-30 Driver

This kit comes with connectors so that you can plug in the power wires from your HID bulb to the stock power connector. However, I did not like that idea because it’s one more place to have a bad connection and there’s a slight chance that a wire can become disconnected. Because of this, I decided to splice the wires from the HID bulb to the stock power wires. If you choose to do this you will also need:

Soldering Iron
1/8” Shrink Wrap
Wire Cutters/Strippers

The quality of this kit (made by apexcone) is very good with the exception of the installation instructions. After reading the instructions I was like WTF? I found a bunch of typos and things were not clear at all so I ended up just throwing them out and figuring it out on my own.

Step 1: Removing The Bumper Grills & Headlights

This is pretty straight forward. To remove the bumper grills all you need to do is pull straight out on them. However, there is a little lip on the piece that surrounds the actual light so you must remove the larger rectangle piece first and then the smaller piece around the light. Next you must remove the headlights so that you can have access to the area underneath the headlight so you can install your ballasts later. To do this you must unscrew three screws. The two in plain view and a third one that can be accessed by a hole in the top of the fender (shown in the top right corner of the picture on the left). As shown below:


Step 2: Removing The Fog Light

There are three Phillips head screws that hold the light to the bumper. These must be removed to pull the light out. Then disconnect fog light from the cars wiring harness. The three screws are shown in the picture below:


Step 3: Drill A Hole For Your New Wiring

Because HID’s require the use of a ballast to create the high voltages they need to operate, all of the wiring cannot be contained in the fog light housing. Because of this, you must drill a 1” hole in the back cover of the fog light for the rubber grommet included with the HID bulb. Don’t forget to seal around the rubber grommet with High Temp RTV Silicone!


Step 4: Remove the H7 Halogen Bulb

To remove the halogen bulb you must first remove the power connector by pulling it straight off. Then you must remove the metal retaining clip by pushing down and to the side to get it out from underneath those two metal hooks and then squeeze the other end of the clip to get the ends out from the little metal holes holding the clip to the bulb’s housing. Then you can just pull the bulb out.


Step 5: Install The HID Bulb

To install the HID bulb just do the reverse of the previous step. Then either connect the power wires to the stock connector or splice them together (the reddish wire in the picture is actually brown. On my 2000 A4 the stock wire colors were purple and brown. Purple(+) Brown(-) Brown is always ground on German cars) Then feed the wires through the hole you made in the back cover of the fog light housing. The larger connector will fit through the hole, it just takes a little persuasion. Then put the rubber grommet in place and seal around the edge with high temp RTV silicone and zip tie the wires together as pictured above. Below is a picture of the wires spliced together. Don’t forget the shrink wrap!


Note: If you choose to not splice the wires together all you have to do is plug the flat square connectors on the bulb's wiring into the stock connector. Also, the brown wire looks red for some reason, but don't worry, it's not red.

Step 6: Install The Ballast:

I found that the best place to install the ballast was on the bottom of the bumper all the way at the bottom right near where the fog light is. This location was easy to get to, was open, and was close to the fog light on both sides. Mount the ballast to the bumper using the supplied double-sided tape.


Step 7: Connect All The Wires & Put Everything Back Together

Reconnect all of the wires, screw the fog lights back to their mounts, pop in the bumper grills, and reinstall the headlights.


Step 8: Enjoy Your Awesome New HID Fog Lights!!!