Tech Article Title Author Date
One piece headlight wiring conversion for 95-99.0 A4 Phil Becker 2004

OBJECTIVE: Not to spend $30 on an updated harness "kit" by using your existing headlamp harnesses and connectors. 

Tools required: 24mm wrench.

Should work with.... All1-piece lamps. 

Remove backing cover from pre 99 lamps (take them out of the car first)

Disconnect the plugs from each of the bulbs inside the cluster. Hi, Lo, fog and brown ground from fog bulb's mounting plate.

With 2-piece lamps removed use 24mm closed end wrench to release the round connector from the rear of your 2-piece lamp housing. It will then drop into the housing so you can remove it. 

Once released by turning the ROUND connector counter-clockwise pull the headlamp's harness out through the large opening on the back of the lamp.

Examine round plug and remove black wire for fog lamp power connection. This is done by pressing in on two small pink clips on the sides of the round connector. See pictures for detail on sliding pink lock mechanism.

You now have a fog lamp free harness that is ready to go into a 99.5+ lamp. 

Remove the back plate from your 99.5+ lamp and remove the rectangular plug from the back cover plate. This takes a little effort and a flat head screwdriver as it is held in place by two pressure tabs that must be released before the connector will come out of the cover plate. Again takes some tinkering but it does come out. 

Remove bulb connector plugs from Hi and Lo beams. 

Insert connectors from pre 99 harness through the rectangular hole on 99.5+ backing cover. Basically swap harnesses... put the pre 99 harness in the 99.5 lamp the way the 99.5 harness was installed. Really Obvious, if you cant figure this out buy a Honda and keep it stock all stock. 

Do whatever you want to with the little connector on the brown wire. I suggest wraping it with some electrical tape or if you have some heat shrink tubing around that works too. Since 1 piece lamps don't have integrated fog lamps you don't need this connector and you've already removed the black wire for the +12v to the fog lamps.

Color Code for harness

Low beam = yellow +12v
High beam = white +12v
Fog lamp = black +12v
Ground = brown -12v

If you are paranoid about water getting into your housings from inside the engine bay then you can put some foam tape on the inside of the backing plate for the 99.5+ lamps. I have not had any problems yet and I did this 2 months ago and I have since driven in the rain several times.