Tech Article Title Author Date
High Intensity Discharge (HID) Xenon Gas Conversion William "Will" Mahoney 2001

Use of the following FAQ requires you to modify (CUT INTO) your halogens enclosures.  Replacement enclosures cost $300+ each.  If this isn't enough of a deterrent keep reading, but you understand that this is at your own risk and the author is not to blame for any problems that may arise.  DO AT YOUR OWN RISK... 

Thoughts and Observations

There has been a lot of debate over the years on Audiworld about how well xenon upgrades work in the halogen projectors.  Mainly people have been worried about the focal length the bulb must be from the projector lens.  Having a set of xenon enclosures in my possession I noticed a few things.  First, the US Specified xenon enclosure lenses does not included a fresnel pattern.  Second there is a block plate inside the xenon enclosure that does not allow direct light to go to the projector lenses.  All the light in a xenon enclosure is reflected inside of the projector.  Therefore there is not a defined focal distance in the xenon enclosure, which makes the various concerns a mute point.


I was part of the group buy with Supreme Power Part (  They offer xenon kits that work with any bulb type.  In the A4's case a xenon conversion for H7 enclosures.   Xenonshop is another popular supplier.

My kit included:

  • 2- D2S (xenon) bulbs
  • 2- Phillips Ballasts (or Igniters)
  • 2- Ballast to wiring harness adapters
  • 2- Big pieces of Velcro


  • Dremel with sanding drum and small diameter grinding wheel
  • Needle Nose Pliers
  • Utility knife
  • Electrical tape
  • Safety glasses
Installation and Halogen Enclosure Modification

First open the hood.  I started with the passenger side light as it is the most difficult/fussy, so while my attention was focused, I removed the two bolts on the top surface.  Remove the intake snorkel to access the back of the enclosure.
Open the low beam and high beam covers.  Disconnect the plugs to the high and low beams.  Remove the enclosure by pulling it to the outside of the car.  There is a pin that this action pulls out.  Disconnect the turn signal.

With halogen enclosure in hand we can begin. 

Let's get started

Remember safety first kids =) use glasses ( I had 4 pieces of plastic bounce off of my safety glasses, not to mention my hairful)


First visualize how the parts are going together (read all of this, try things, etc)

Remove the H7 bulb from the low beam projector.  Install the xenon bulb. *WARNING* Do not touch the glass portion of the bulb.  If you do wipe it down with rubbing alcohol.


Bend the retaining clip using a set of Needle Nose pliers.  I took the contact portions and spread them apart from each other.  Fasten the retaining clip to hold the bulb in.  

Afterwards, You may want to just play around with the ballast and cable to get an idea.  I is a pic...

Take the Dremel Tool with drum sander and use it to remove material in the ballast cutout.  You are basically shaving the edges down so the ballast can sit at the bottom of the OEM ballast area.  A lot of trial and error.  Try to limit the removal to the ballast size.  I removed all the plastic from the inner lip to the outer lip. Be careful you can form a hole through the side.  NO biggie if you do.  I made a few.

When the ballast "dry fit" on the bottom.  Position the connector in the inside, aft corner of the respective enclosure.  Scratch/draw an outline, and use the utility knife to cut the opening. 

Take the electrical tape and cover the plastic areas that were drum sanded down, and roll over the edges of the hole/cutout. This prevents chafing of the electrical cables.

Home stretch! 

Apply one side of the Velcro to the former halogen enclosure.  apply the other to the back side of the ballast, so it will line up when installed.

Run the xenon cable connector into the hole.  Plug in power adapter harness.  Velcro the ballast to the housing.  Feed power adapter lines through.

Plug on (push and twist motion) the xenon connector in the orientation shown in the mock up.  Place splash cover on the low beam. 

A lot of people have asked me if I am concerned about condensation from having this hole.  I am not because of a few things.  First there is still a lip and the brace below the enclosures to prevent water splashing into the enclosure.  Second, I had a set of xenon enclosures in my car for several months, and I do not remember ever having an issues with condensation. 

I'll keep an eye on it. If it becomes an issues I will do Option 1 or 2.

SPP says to drill two holes, but I'm not sure how you are supposed to put a big fat connector through it.  I tried to disconnect the cable from the ballast.  No luck.

Optional Step: Condensation 

Option #1:

I had originally thought of putting a cover over the entire ballast, but did not because of the tight fit.  

If condensation becomes an issue I will fabricate a half cover that will screw into the enclosure provided holes.  I have vinyl, rubber, and other plastic sheeting that I can heat form to shape.

The half cover would cover the cables and hole.  

If anyone want to do this install in CT/NY, I am happy to help.  We can do this step.

Option #2:

Hold on to the square pieces you removed to run the cable.

Once you have run the cable, notice where the cables are located.

Take the square piece you cut out.  Drill a 3/8" hole, with the hole just touching the edge for both the cable and power wire bundle.  

Take the utility knife and form the holes into slots leading from the edge.  

Lift ballast off Velcro and replace plastic square in opening.

Fill voids with silicone, or cover with tape

Put enclosure back in car.  If your ballast is sitting properly in the enclosure, you should not have a problem.  Remember to reconnect the turn signals before installing.
To power the ballast, plug the red spade connector into the red wire plug for the low beam and the black spade connector in the brown wire plug.  (NOTE:  High Beam connector is Purple and Brown)

You may want to change the headlight fuse to 15 amps. But may not be necessary.

Repeat for the other side and you are ready to go!

Follow the Tech Article for aligning headlights for an optimum output.


Voltage Issues

Many people, including myself have gotten voltage spikes/drains when activating the xenons. My stereo would enter into safe mode, and my warning lights on the dash would flash momentarily. My solution was to create localized grounds for the xenon ballasts. I purchased large automotive grade wire (12 gauge I believe) from my local car parts store. I also purchased two female spade connectors and two ring connectors. I ran the wire into the housing and out to the front bolt on the fender. I ran the line up through the hole (see pic) and placed the ring connector under the bolt shown. I tried to minimize the wire length for both sides, so I cut the wire down before attaching the ring connector. I wasn't sure that it was going to work but it did. 

Good Luck.