Hello all, I'm just finalizing a few things on my series1 1981 400i before I remove the car from winter storage. I'm installing the Hill Engineering steering wheel hub spacer along with a Nardi/Momo adapter. I'm also attempting to get the horn working again. I removed the compressor and cleaned it. The horn works when removed from the car. All my searches on this site tell me that there should be a wire connected to the horn button. There is no wire to be found! I removed the dash panels surrounding the steering column and I cannot find a loose wire or obvious connector anywhere. I understand that this airhorn may have been disconnected during federalization back in the 80s, but would they have actually removed the entire wire from the harness? I also have a theory that maybe the steering shaft is the ground? The button looks brand new as though there was never a wire connected. My measurements suggest that maybe the electrical connector on the rear of the button actually connects with the steering shaft when pushed? Any info will be appreciated... Thanks, Jeff
If you do remove the wheel hub, you can see the stalk. There is a curcular disc with a wire riveted, this wire jas to pass through the hub up to the horn button.
I have the hub removed and I did see the small wire on the disc. It was quite short. I will be with the car again tomorrow and will look closer at the disc. Thanks!
I spent a lot of time with this horn wiring due to random horn honking while turning the wheel. I eventually solved that, but I learned quite a bit about that little wire. Here are the basics. Power (+) to horn or horn relay is on full time. The wire to the horn button is the ground. You are correct that the ground is actually the steering column housing bolted to the chassis. The metal disc allows the wheel to turn without twisting the wire when turning the wheel. The wire on the bottom of the disc needs to run to the Ground (-) on the horn or horn relay. It sounds like that wire got clipped off at some time. The wire runs down the center of the column housing, out to a harness under the dash and eventually to the horn or horn relay. When mine was federalized, they just disconnected the air horn and wired a new funky vibrating horn behind the radiator. I removed that horn and went back to air horn that was still sitting behind the front grill. Ken '84 400i Series 2
The issue I got with the honking horn was that one of tab of the ring disc tab is now weak. As a result the disc is not perfectly flush (slightly above its normal position) and the rivet that bolts the wire on the disc bumps against the vertical reinforcement slots of the hub. All I had to do was to cut a large piece of plastic roughly the shape of the stalk ring. This is is placed between the stack and the hub and insulates the rivet from the hub. No more issues! Will try to grab some pictures.
See the black spots on the hub? That's where the rivet (holding the wire) was rubing against the hub. Quite easy to isolate once you figure out the issue. Image Unavailable, Please Login
Raemin I was able to fix the horn honking by just bending the offending tab back flat and out of harms way. It was not worn, just bent up. Ken
1) I had already dismantled that beast twice 2) my young kid kept on saying "it's embarassing" while I was parking the car. So "belt and suspenders" approach!
