Horn Honking Without Reason.

Horn Honking - Horn seems to honk for no reason or when one steps on the brakes?

That’s not a safety feature it’s the deterioration of the rubber mounts under the airbag module that keeps the horn contacts open until you press on the Air Bag/horn pad. Some purchase a replacement frame inside the steering wheel that comes with new rubber parts installed for about $100. Others buy exact rubber mount replacements for their existing frame from Zims Autotechnik or at FVD Brombacher. The Zims solution seems to be an all rubber insert that replaces the existing rubber mount. The FVD solution

The FVD Mount

 appears to includes outer & inner metal collets and seems like a more robust solution although I have not personally tested them. Guys like me do the fix with a few dollars in O-Rings. The horn in my car had gotten to the point where if I

Zims' Mount

 accidentally brushed my hand against the airbag/horn pad the horn would sound.

Here is the fix I engaged in:

• Disconnect the battery first! Do it for safety and to not triggering an airbag OBD fault & light. Do not reconnect it until you are done and the steering wheel is completely buttoned up.
• To get to the horn pad mount loosen the two screws through the back of the steering wheel. The screws remain inside the steering wheel once loosened. Use the appropriate star drive wrench to unmount the airbag/horn pad. The first time I did this I used an Allen wrench and it worked without stripping the heads of the fasteners, your experience may vary. You may need to cock the steering wheel slightly to the left or right so your tool has a clearance between the wheel and the dash to get it in position.
• For safety, I unplugged and set aside the airbag/horn pad making it easier to work on the frame. This can also help in avoiding damaging the wiring harness behind the pad.
• Remove the horn pad frame by unscrewing the 4 large hex head screws (on the factory 4 spoke steering wheel) and unplugging the frame's grounding wire. The frame also serves to capture the two star-drive screws you originally loosened to release the airbag/horn pad so keep track of them while slowly lifting out the frame.
• Use some very fine sandpaper; I used 1500 grit, to polish the electrical contacts on the horn frame and the matching steering wheel contacts.
• Adding O-Rings to each of the rubber mounts has two purposes: 

  

  Rubber mounts on the horn
   frame

  
  
• One is to stabilize the movement of the frame.  Using two smaller O-Rings on the front and back of each mount will not change the gap between the switch contacts but will firm up the amount of force needed to actuate the horn. 
• The other is to increase the distance between the horn contacts. Using a small and larger O-Ring in combination on the back of the frame mounts between the frame and the steering wheel will increase the stand-off of the horn contacts.
• Turns out I had to fine-tune the number and size of the O-Rings to adjust the pressure and stand-off required to stabilize the frame while not making it too hard to actuate the horn. This was done by trial pressing on each corner of the frame once the frame is reinstalled developing a feel for how much force is applied while listening for a click when the electrical contact in each corner comes together. This will probably vary based on the condition of the original rubber mounts on the frame in your car. For this reason, I suggest the purchase of the $5 O-Ring assortment at Harbor Freight to allow for flexibility in the number and sizes of the O-rings used. 

  

  O-Ring Assortment
  
  

  
  
• I also used a little contact cement to tack the O-Rings in position during reassembly. If needed only a tiny dab should be applied.
• Once you have arrived at the proper number /size/placement of the O-Rings be sure to pre-position the two screws that hold the horn pad to the frame before fixing the frame in its final position. An easy way to do this may be to tape the screws in position on the frame with a strip of electrical tape and once the frame is positioned pull the tape off the screws.
• Button things up in the reverse order. Be sure to not use too much force on the large hex-head fasteners or the pad hold-down screws on the back of the steering wheel. Snug is all that is required.

I give this job a 2 on the 1 to 10 Home DIY difficulty scale. 1 being replacing a burnt-out cigarette lighter and 10 being replacing the steering rack.

3/19/2022 -- I have now had this solution in place for over 10 years and the horn pad still works properly

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#horn #airbag #steering