Hi. My old E220 (2002) is still rumbling along but I have an issue with the front right indicator. Changed bulbs, swapped the bulb insertion holder - just doesn't work. Dashboard brings up the indicator fault and the front foglight flashes instead. I've looked through a few forums and discovered that this is a common issue with the C series as well - basically the connectors inside the lamp holder of the headlight unit get corroded. Tried sanding, cleaning and can't fix it that way. So, the workaround is part number A2038260182 that takes a supply from the wires to the headlight unit directly to the lamp holder. Only issue is that I don't know which wire to cut and insert into the new part. Essentially, 4 wires - a browny red, a yellow, a white and a blue - see pic. Anyone know which one to use? Bought the part for £20 which is a better option than spending about £150 on a new unit and removing the bumper to get it in.