I have two horns (the high and the low) from my 300TD 85 MB that respond to a 12 volts DC battery source. It's not what I'd call a horn but it is something. As for the horn wiring...I can't seem to get 12 volts to pass through to the horns when we press the horn. So it looks like I might need to rewire the thing...but I haven't a clue where to begin. I can't even figure out how to look under steering wheel at the contacts. Any suggestions?