Remove the rubber boot around the base of combination switch, just move it out of the way so you can unfasten the two brown wires going to the horn ring contacts. Pop the horn ring contact unit out of the casting. The two brown wires will follow if you have them disconnected at the turn signal combination switch. It's a common part on most Mercedes sedans of the era. If you can't find one locally, I probably have a couple dozen good used ones around here!
