Hi,

Since I bought my B6, the headlamp switch cluster has failed to illuminate at night (only the fog lamp symbols & the central knob were illuminated).

I decided to take it apart and see if I could fix the problem. It turned out that the top two LEDs are wired in series.. so whilst only one of them had blown, it was preventing the second one from working.


1. Take your headlamp switch cluster out of the car - press the knob in and turn to the right, then pull the switch cluster towards you to get it out.

2. Bring the lamp cluster inside and dismantle it. Hopefully the photo below will give you an idea of which parts are supposed to separate:



Once you've un-clipped the front shroud from the back part (with the connectors on it) you can then gently rotate the switch knob and it will separate from the back part.

The circuit board pulls away from the back part (it's a clever little design, the wires just pop-out of the metal receptacles).


3. Using a 12v power supply (from digital picture frame!) and some crocodile clips, I hooked-up the power to the contacts to illuminate the bulbs. Sure enough, only a few of the LEDs light-up.



Note: I just used trial & error to find which contacts to connect the power to! I blew one of the central LEDs in the process - make sure you use the right contacts as indicated above (the red lead is positive, the white lead is negative).


4. Using a 5v LED that I had in my electronics kit, I pressed the legs against the solder points of the broken LEDs - it didn't light-up.

Most LEDs are polarised, so I reversed the legs and sure enough, the LED light-up AND the other LED light-up too, indicating that the LEDs were wired in series (the anode[-] of one feeds onto the cathode[+] of the other).

You can see in the photo below, I temporarily attached the legs of the replacement LED and suddenly the circuit is complete and everything lights-up (apart from the broken LED obviously).




5. At this point, I noted down the polarity (which way round) the LEDs needed to be soldered in by colouring the Cathode[+] with a permanent marker.
I then de-soldered the broken LED and the LED next to it (just to ensure both LEDs were of the same type / brightness) and replaced them with my new LEDs. I also replaced the central LED I blew-up earlier when finding out which contacts were +/-

The Photos below show the back of the circuit board (before replacing the LEDs) and the front with the replacement LEDs soldered in! It's important to re-attach the power for a quick test before you re-assemble the switch!





6. Simply re-assemble the lightswitch cluster in reverse order and you're ready to stick it back in the car!

My Blackberry was unable to take a very good photo, but the illumination was pretty much back to normal!



If you've found the above useful, please show your appreciation by clicking on the button in the bottom-right hand corner of this post.

Al.