There you go.
Killerhertz of this forum also did a very neat job with some replacement combined foglight/DRLs and a howto - I think it is in his modding thread.
This 'howto' is a simple way of converting foglights on a w203/209 to DRLs
To give a more 'modern' look, I used LED bulbs - on the A209 these were H7. Get the best ones you can.
My vehicle had AMG styling - this meant that there was a plug/socket within 3 inches of the foglight. This made the overall install simple.
Black wiring was used throughout as this hides better than coloured wiring.
A dimmer unit was bought from E-Bay - a search on E-Bay for ‘DRL dimmer’ will throw up several.
Start on the nearside. On the 209 the foglamps are accessed from a panel under the lamp. Drop this down to remove the bulb. The small grill held in with three small Torx screws should be removed to make access easier. The bulb and holder rotate around 45 degrees. Note the position of the holder when it is released as it is not obvious how it goes when it is refitted. Disconnect at the connector and remove.
Remove the existing incandescent bulb, make up a couple of fly leads, connect them to the bulbs and splice into the existing vehicle wiring. There is no need to observe polarity. Locate the bulb where any heat generated will not damage anything. I hung it from the headlamp washer pipe where is was secure, but not touching anything. Test that the bulb illuminates when you turn the foglights on.
All of the above is to defeat the bulb failure circuit without adding resistors etc. The bulb will light up if you lock/unlock the car or turn the foglights on and can be seen through the small grille but does not cause dazzle or distraction. I think the diamond pattern looks quite nice . You can of course put resistors there but there is little to be gained.
Now splice into the short fly leads from the bulb holder. run one cable to earth - you can use the earth on the vehicle harness - this is the brown wire, or a convenient ground stud. The other cable should be long enough to reach the headlights on the other side.. As an LED is polarity sensitive, ensure that the correct polarity is observed - you can test by touching the end of the long wire against a live point - horn (ignition on) or lights (lights on)
Once tested replace the bulb holder with the LED bulb in the foglight. Ensure that this is fitted correctly as water will get in if it isn’t.
Route the cable to the offside - I routed mine behind the spoiler with some cable clips.
Now do the same for the offside foglamp. On the 209 it is then easy to route the wires up behind the offside headlamp.
Now fit the dimmer unit according to its own instructions. You will need an earth - use an earth stud, there will be one on the flitch panel, a sidelight feed - you can tap into this without removing the headlamp bulb cover - the wire will be grey with a tracer (red or black iirc), the wires to your DRL bulbs, and an ignition feed. To get this, run the wire from the dimmer unit alongside the existing harness to the fusebox/SAM located up by the wiper linkage. There are a number of entry/exit points you can push the wire through. If you use black wire it will hide well.
Locate an ignition live in the fusebox/SAM this could be the horn fuse using a piggyback fuse (Halfords), or in my case because space was tight in there, I used a feed from an unused relay that became live with ignition on. Test with a testlight and it’s simple to put in an inline fuse.
I don’t need to stress too strongly that an appropriate fuse (say 5 amps) should protect this circuit at the fusebox.
Now test it all. DRLs should be on with ignition, and go dim with sidelights. Old foglight bulbs will shine through the grilles when locking/unlocking or if front foglights are turned on.
The dimmer unit can now be ty-rapped to the harness and pushed under the slam panel - out of sight and out of any water and crud.
Last job is to put everything back, make good, ty-rap all wires, and bask in the warm glow of a job well done (and a single malt).
They actually look much brighter than in the photo, more like an OEM brightness.
