Tech Article Title Author Date
City Light Wiring for Pre '99.5 with Euro Headlights Jim Baulsir 2001

I wanted to upgrade the lighting on my 1998.5 A4 and after looking at all the options I decided to get the euro S4 two-piece xenon headlights. As these are European spec lights they naturally came with a small 5-watt light called a "city light". Of course, the US models don't have the wiring for this light, so here is the modification I made to make the city lights work.

Design Parameters:

  1. City lights to be on when the parking lights were on.
  2. City lights to be off when the lo-beam headlights were on.
  3. City lights to be on when the parking lights were on and hi-beams flash (who cares, can't see'um anyway).
  4. Make minimal changes to the car's wiring harness.
  5. Have plug and play backward compatibility in case I needed to re-install the original US spec headlights.

This modification was done on a 1998.5 Audi A4 5 speed with trip computer; the stock headlights (with integrated fog lights) were replaced with euro S4 xenons (two piece).

Note - Original Fog Light functionality was lost when stock headlights were replaced. I am planning to add lower grill fog lights at a later date. This is why I didn't use the fog light circuit to power the city lights.

Parts Needed:

  • 2 - P/N 000-979-117 Audi Wire with Socket
  • 2 - Directed Electronics Inc. 8617 Relay Assembly
  • 1 - Radio Shack Double Sided Tape Cat. No. 64-2361
  • Electrical Tape
  • Some method of splicing
  • Shrink Tubing

Tools Needed:

  • #30 Torx driver
  • Philips screwdriver
  • Needle Nose Pliers
  • Slip Joint Pliers
  • Soldering Iron
  • Solder
  • Wire striper/cutter

Standard Disclaimer - Do this at your own risk. I take no responsibility. Works great on my car. Your mileage may vary. Don't call us, we'll call you. In the event of an emergency put your head between your legs and kiss you nice car good-bye. Yadda Yadda.

The Circuit:


Click for a larger image. Note: Xenon ballast omitted for clarity.

Power The City Lights:

Remove the corner lights, and the headlights, disconnecting both plugs, set-aside on a towel. Cut one socket end off of Audi Part #000-979-117, cut it off right at the socket as you will need approximately 12 inches of wire remaining to route it over to the corner light. Roll back the rubber boot on the headlight connector to expose the purple socket frame. Push the cut end of Audi part #000-979-117 (from the inside) through one of the existing holes in the back of the boot. There are two clips on the sides of the barrel that need to be gently pushed in to release the sockets. Do not remove any that are already there, just insert the new socket into position #1, and click the purple barrel back into place. Note: If there is any resistance, don't force it; one of the sockets is not seated, just make sure that they are all pushed in and try again. Roll the boot back and dress the new wire along the outside of the headlight harness approximately 5-6 inches (I used black electrical tape).

The Splicing Part:

Dress the new wire around to the corner light harness and run it down to the plug. Locate the parking light wire (on my car it was black with gray on the drivers side and black with red on the passengers side) use a voltmeter to verify (Remember -- Measure twice, Cut once). You can use whatever method you choose to splice the new wire to the parking light wire, but I cut, soldered and covered with heat shrink tubing. Then dress the wire back on to the corner light harness again using electrical tape; just remember to account for a service loop so you can work on the lights later.

The city lights should now go on when you turn on the parking lights, test to make sure.

The Inside Work:

I wanted to place the relay and wiring inside the headlight itself because its relatively weather tight and with the connection just made, I had the three things I needed, Parking light power, lo beams power (12 volt of course), and ground.

Unplug the 12-volt input to the ballast and remove the back cover from the headlight, then (read caution) disconnect the high voltage cable from the back of the xenon bulb and set aside. Unplug the high beam and the city light (entire bulb comes out). Push the lo-beam 12-volt lead into the headlight housing by gently depressing the four tabs on the rectangular cover it comes out of. Using slip joint pliers, gently grab and rotate the main head light plug clockwise so the tabs lineup with the slots in the housing. Now remove the internal wiring harness and lay it on your workspace.

Connecting the Relay Coil:

Shorten the wires on the relay harness to make it easier to dress them in on reassembly (approximately 4-5 inches). Connect the relay pins 86 to 12-volt power for the lo-beams and 85 to ground (connector pin 5 being 12-volt and pin 2 being Ground). Again use any splicing method you are comfortable with, I soldered the leads to the actual pin in the connector (using the same procedure as above to remove and reinsert the pins). Caution: this required some VERY intricate soldering with a low wattage soldering iron so as not to destroy the pin and burn the insulation on the wires.

And Now The City Light:

Cut the wire going to the city light (gray in my headlights) and splice (insulate with shrink tubing) the connector side to pin 30 of the relay and the wire going to the bulb to pin 87a (this is the normally closed contact of the relay). Cut the wire to relay pin 87 and insulate it, as it is not needed. As for mounting the relay, I used some high temperature double-sided tape (I didn't want to drill a hole in the headlight) and stuck to the bottom under the high beam. Now reassemble headlight.

Test, install, do the other side and re-aim your headlights. A good procedure to aim e-code headlights is located at: http://lighting.mbz.org/tech/how_to/aim.

Thanks to Todd Becker's BOSCH Euro Headlight Installation (for pre '99.5).

Please send corrections, comments or question to the author.