933 horn/Airbag problem

tjbrune · 07-12-2005, 06:34 AM

I've had a problem with my horn sounding when breaking / turning without wanting it to.

I have a 95 933 cab C-4.

My mechanic told me that the air bag apparently sets on top of the horn activator (my term) around the steering column, and put pressure on the horn, and it sounds......especially when breaking.
He said that it was redesigned in 96, but the redesign won't fit my 95 model, so replacement of the whole new assembly is above $ 1500 or so if I remember right, anyway a lot more than I wanted to pay. Surely there is a way to add bushings or something to keep the pressure off the horn.

I have just had the horn fuse out, but I need a new inspection sticker, so I need the horn working..............preferably prperly.
thanks for any help.

tim

derkpitt · derkpitt's Garage

Same problem on a friends 98 911.
Remove the air bag and bend the horn contacts. You'll need a very long torx bit to do this.

Removing the air bag even with the battery disconnected trips a warning light, I think in the tach.

It cost him $50 for the dealer to reset the light with their special tool.

sthorpe · 03-06-2007, 12:54 PM

Can anyone point me to a site that walks you through this process? A site with pictures is always helpful. Thanks, Sean

rattlsnak · rattlsnak's Garage

Sometimes bending the contacts wont work. What happens is there are rubber grommets surrounding the 4 screws that hold the airbag mounting plate on and they crack/rip and you lose the "springing" action that you feel when you push the horn and the contacts just rest against the grounding points and the horn sounds all the time, or when you breathe on it! I had the same issue and didnt want to spend the $1,500 either, so I took it apart and installed a slice of a rubber hose (like a fuel line) and made my own grommets and it works fine. If you disconnect the battery first, it shouldnt set an airbag light on, but remove the airbag, 2 torx screws at the 3 - 9 position, unplug it and you will see the mounting plate. It has four bolts that hold it on. You can push on the mounting pate and see how it works. If bending the corner tabs outwards works, by all means do that, if not you might have to make your own grommets. Usually only 1-2 will work, dont have to do all 4.

Cooper911SC · 03-07-2007, 07:58 PM

No problems with horn here, but I recently pulled the air bag and steering wheel from my 993 so I could remove the tach to have the housing replaced...anyway, I didn't disconect the battery, I just removed the air bag and wheel and made sure not to turn on the ignition key while the airbag was off. No problem with lights or codes.

Thanks for the post...I'll know what to do if my horn ever goes haywire!

Good luck, Cooper

Don Plumley · Don Plumley's Garage

You should always disconnect the battery for at least 30 minutes before messing with an airbag. Period. It's an explosive device.

This isn't about not tripping the indicator light, it's about letting the capacitor discharge so you don't accidentally discharge the bag.

Cooper911SC · 03-07-2007, 08:55 PM

Thanks. You are right.

sthorpe · 03-09-2007, 04:10 PM

Phew, I just read this, and it didn't explode. That is good news. Equally good news is that I added four tiny washers to the four bolts that hold the airbag bracket. These are about 1/16" in thickness, and created enough space to solve the problem. I feel like i just saved $1,500, which is another good thing. I did not turn on the ignition during the entire process, and no airbag warning light tripped.

Thank you all for the feedback.

I also replaced my front hood struts which was quite easy, given the post elsewhere on this site, and the dental floss recommendation.

I went to do the rear struts, and unless I can turn myself into a 3" human and climb in there and do it, I think I might pass. Pretty tight quarters in there. Unlike the front, where one end just pushes on, both ends have the clip/pin attachment, which will make the inside end next to impossible.

Unless anyone has some tricks that I don't know of.... (?)

Cooper911SC · 03-09-2007, 05:39 PM

sthorpe- To do the rears you have to remove: 1) the air cleaner lid and filter. Then just reach back there and go for it. 2) for the left side you need to remove some of the plastic ducting for the HVAC system. If you study it you will see that it is held on with a few 10 mm bolts and some screws if IRC. A couple of the screws are kind of blind on the left side of the fan unit. They are cap head allens I think. Once this is out of the way, reach in and go for it.

A telescopic magnetic is very handy should you happen to drop one of the clips.

Good Luck, Cooper