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W222 2014 s class Horn issue

I own an S Slass W222 2014 Long wheelbase model.

Recently while driving the horn started going by itself without any reason, this went on for about 2-3 minutes and then horn stopped working.

Since then I have replaced the Horn relay and also checked the Horn fanfare fuse, they are both fine.

Also the horns do work when i lock the car which is very strange

The horn still doesn't work, I would prefer to diagnose and fix this issue myself, Does anyone know where are the actual horns are and how should I replace them?

Any advice would be highly appreciated

Thank you

Alan

sounds like the contacts in the steering wjeel may be making contact... has the cars airbag been changed?

Thank you for your reply

No the airbag or the wheel have never been touched

Kongnister where are you?? He's the guy with ALL the info on MB's you'll ever need. Haven't seen him around as of late. Is your car CPO or extended warranty? I had that happen on a Porsche once! You got lucky when it went off in three minutes! Mine was blowing ALL the way to the dealer LOL!

good luck.

Yep, PM konigstiger to see if he can get you the relevant diagrams.

Right, I's sure he'd appreciate the correct spelling more :)

it looks like it might be the steering wheel contacts causing this issue as the horn still works when i lock the car, anyone knows how should i go about opening and investigating the steering wheel? there is no guidance anywhere on the internet, Dealer said £168 just to investigate the failure, i would prefer not to go down the dealership path if i can help it, dont know how to contact konigstiger

I had read an erratic horn issue that turned out to be a broken alarm module in a friend's BMW . In that instance, he said his cars horn went off in the middle of the night without any reason

Does anyone actually know how should i open the steering wheel, take the airbag out? there are no pin holes at the back, do I need to make holes by pressing into the space available? i would rather not make holes if i can help it, any help is highly appreciated

a quick progress update

after disconnecting the battery I took the airbag out of the steering wheel and found nothing wrong, All cables are connected just fine, no issue with the electronic board either, i am really confused what to do next, any advice from anyone would be appreciated

Attached wiring diagrams may help.

Problem resolved

https://cimg0.ibsrv.net/gimg/www.mbw...a032d449d.jpeg
https://cimg1.ibsrv.net/gimg/www.mbw...d99d98af4.jpeg
https://cimg2.ibsrv.net/gimg/www.mbw...9d7747d34.jpeg
Please see below steps I took to resolve the issue

i refuse to take it to Mercedes for them to charge me £170 just to check this tiny issue

1. I disconnected the battery which is in the boot and very simple to do after which you must wait 30 minutes to stop airbag blowing on your face.
2. I took the airbag out of the steering wheel which is very simple by pushing inside the holes with screw driver behind the steering wheel, remember you have to break the leather seal to do this.
3. Open 3 holes and take the horn plate out
4. Disconnect all of the cables from the plate which you can see in the attached picture.
5. I quickly discovered that one of the connector marked red had a tiny hole inside, after checking with multi meter I could see it was not conducting electricity.
6. Using hot soldering iron I just dropped a tiny amount of solder which resolved the issue
put everything back in the same order and your issue is fixed

Glad you worked it out, well done!

Great job, good to see it was fixed

Quote:

Originally Posted by Illusionist (Post 7618080)

There may be a reason that connecter overheated to cause the original problem. Keep an eye on it..... Time will tell... Just like blowing fuses, replacing the fuse is not the fix, something is causing it blow..... Excellent DIY job !