been searching around without much luck, I've got an issue with my horn with my 1979 240D. Every now and then they will work and I've even tested to see if there is power going to the horn when horn pad is pressed. Yes power is going but still no sound. When I probed the two contacts that screw on to the horns, one is getting 12v and the other is not since I'm assuming that is the ground to the horn. When I connect the horns directly to the battery, they do come on. I'm thinking that I have a bad ground on both horns. Could I just wire a new ground to the chassis?

So, I'm hoping to I could find the horn wiring diagram to help me trace where I'm having the issue.

Sure is an earth problem . But just might be the horn push ring . Inside the horn push you will find that the horn push contacts run on copper ring and they are not tuching .Thats the earth for the horns .

I did remove the horn pad and everything did look correct, good contact, no corrosion

Here it is from a late model 300D turbo. It is basically the same as a earlier 300D NA, minus some extra stuff on the ground that is irrelevant.

thank you!

Do you want the grounding locations? I don't know what I can dig up, but if you want I can give it a look.

yeah, that would be great!

Prolly grounds through the mounting bolt. Remove horn and clean the contact areas.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.