linderpat

Our cars have two horns, located in the front right-side fender well, near the retractable headlight. One horn is a high-pitch horn (mounted on the right side of the bracket holding them to the body) and the other horn is the low pitch horn.

My hi-pitch horn suddenly stopped working. The low pitch works fine. I checked the relay (good; to be sure I also swapped with another relay and no difference. Low horn works, hi horn doesn't); checked the fuse - fine, not blown, and checked the wire harness - no shorts. The problem is a dead horn.

I pulled it off and took it apart. I can't see that anything is wrong. Has anyone ever fixed one before? How did you fix it?

Absent that, I need a new one (used is fine). Does anybody have one that they would like to sell? Part number is 911 635 101 20 (or 21 for the short version according to PET)

SteveG

Ed: Have you put the unit back in place and tested it? As always it may be ground or corrosion problem at the mount, although in the past when I had that problem it resulted in the horn being activated when not wanted, not dead. That was a different car, the mount to the chassis was the ground. YMMV Still it may be a corroded contact or wire.

kmascotto

I was in there looking at my horns a few weeks back and I noticed the horn that mounted to the outside of the bracket, had broken off. I secured it temporarily, but i want to mount it back in its original location. When it broke off it took a piece of the mounting bracket with it, so I was going to weld that part of the broken bracket back on...

Any suggestions on the safest way to weld something like this on a 928??

WyattsRide

With the horns out, can they be tested on the bench with a battery?

linderpat

Steve - the wires are good. The mounts are all nice and clean and bright, as are the contacts with the horn. I actually swapped wires with the good horn, and it works fine. The bad horn just appears o be dead.

Rick - I did try it with my bench battery, and no joy. I will try the bench battery with the good horn to see if that test works.

Alan

The two horns are in parallel driven by the same relay. Only the wiring between the horns can be suspect if one works. Just apply 12v directly to test any of these horns. Since the 928 horns are often weak sounding you can replace both with Hella Supertone twin horns for a more assertive sound (may be more cost effective too?).

There is no corrosion at the horn connections that will ever activate a horn without other issues elsewhere - its just not possible on a 928, and I can't imagine how its possible on any other car either. Any corrosion affecting operation here would need to be very local to the paired horn wires - it's all right there.

Just unbolt the horn pylon from the frame rail (3 bolts IIRC) and have it welded off the car, easier & safer


Alan

9two8

I think the horns are made by FIAMM, Italy..., you,ve nothing to lose I guess, so try pulling apart the cylinder where the wires connect to, once apart you can see the inside wiring. The wires from the solonoid windings that are soldered to the circuit could be suspect, try re-soldering these, as you say it,s dead thats all it could be ?

Ken
80 928 S
5 Speed

UK

kmascotto

Just unbolt the horn pylon from the frame rail (3 bolts IIRC) and have it welded off the car, easier & safer
Alan[/QUOTE]

Sweet, thanks Alan. I did't think that was an option...