can somebody please correct me if I am wrong but this is what I have figured out thus far for a W124 E420.

obviously, brown is ground - pin # 4
white/red stripe - fog - pin # 1

now here is the tricky part....solid white (pin 2) and solid yellow (pin 3) connect to the H4 bulb, but which is low beam and which is high?



*EDIT*

Okay I think this is right. The yellow wire, pin 3, horizonal terminal on the H4 bulb is the high. The white wire, pin 2, parallel to ground on bulb is low beam.