R129 Horn Problem

[Mike Miller]

I'm looking for some help from my R129 Buddies. Especially the 90-92' owners.

My horn has been acting up. It was intermittent, requiring steering wheel movement to get any action so I figured it was not the horn relay, located in back of the fuse box, left rear hood. I removed the air bag to check for wires or bad slip ring. What I found was a horn relay in the cavity!! This threw me off. I checked the integrity of the wiring to the relay and cleaned everything, without removing steering wheel or messing with the slip ring. The horn appeared to be working again. I put it all back together, the horn worked three times and quit completely

I will take any suggestions or experience stories. I would also like to know if that relay in the steering wheel is supposed to be there. It seemed funny as it did not have a MB part number or star on it (made in Portugal) and ALLDATADYI does not show it as part of the assembly.

[chicane]

I'm having the same problem. My horn worked intermittently and then has stopped all together. I took it to my local indy garage and they checked all fo the same things (relay, contacts/swith in the steering wheel etc) and couldn't find the cause. They think it may be something like a broken circuit or other electrical fault.

Unfortunately I think I'm going to have to take it to a dealer as the indy's diagnostic computer didn't pick anything up. I'd be very interested, like Mike, in hearing of anyone else who has had similar issues.

I need to get it sorted soon as it needs to work to get the annual MOT!

[Mike Miller]

I thought, what could it hurt, I don't have to buy it after they do the research. So off to the dealer to "buy" a new horn relay. The one I mentioned above that is under the drivers air bag. Well, what do you know, no one could figure out what I was talking about. Not even their most expereinced mechanic. They all wanted to sell me a relay that plugs into the rack at the back of the fuse box. My car does not even have a receptical for that relay there!!!

I'm lost. I am afraid to hook it back up as it is shown in the manual (no relay) as I don't know what else was done to the system and I don't want to use a relay that doesn't belong IN the system.

I am depending on you guys.

[tecqboy]

Does the horn "itself" actually work? That is, if you connect it to a 12 volt source directly ( battery ) does it work? Horns get water in them, rust and fail, sometimes intermittently.