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Newbie/ Silent Horn


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R1200RT 2010

Purchased in 2012, as the second owner.

Some months ago my horn operation became intermittent,and now it is dead. I have no voltage at the horn itself when the button is depressed. All other switches operate normally. I am not eager to trace the wiring, and would rather not purchase another cluster fu**, I mean, multi function switch. BMW insists they do not have wiring schematics or diagrams. This makes it difficult for me to determine if the switch is the cause, or a broken wire in the harness somewhere. Wire color codes or any info would be greatly appreciated.

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Morning Tinkerer


Unfortunately your horn is computer controlled by the chassis computer ( ZFE).


Assuming BMW hasn't changed the wire colors-- when you push the horn button it connects the Brown/Yellow wire to the Brown/Black wire & that tells the ZFE (chassis computer) to send power to the horn.


IF, you high beams work & your flash-to-pass works then that tells you the Brown/Black wire is probably OK (again assuming BMW hasn't changed wire colors) so that leaves the horn switch itself, or the Brown/Yellow wire between the switch & the ZFE, or something wrong in the ZFE, or something wrong with the wire between the ZFE & the horn connector.


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Someone will correct me if I'm wrong, but I think there is a service campaign to replace the handlebar switches with a newer version. Are your switches original?

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I have a 2012 and there is a campaign currently on my bike to replace both switches. My dealer has them on order and will have them replaced when they arrive. I had the left and right replaced already. BMW has different p/n's for the ones they want replaced. When my switches were replaced they said these are the good ones and I should be OK. Well it looks like maybe its not OK.

Check with your dealer and see if they need to be replaced. Even if it does not fix your problem they will more than likely have to be replaced under the campaign issued. Campaigns stay with the life of the bike even out of warranty until accomplished.

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On my 2012 the left switch was replaced at the first service, horn was not working. It was the dealer that pointed out the the problem, guess I use my brake instead of the horn!

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I'm not sure how to determine the wire colors from the horn switch without opening the "multi function" switch, which I understand is easily disabled when opened.

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Thanks for the info, I'll check with my dealer today. I checked voltage to the horn again yesterday as the horn began working intermittently. This leads me to believe the problem is a poor connection rather than the computer. (Is it a computer or more of a Logic Controller?) I was able to confirm that when the horn does not work the Grn/Blk wire at the horn goes low. This is something at least. I have not stripped back the harness covering at the handlebar or from the horn, but I guess that's next, unless I shell out 3 bills for the 911.

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I have no documentation from the previous owner suggesting the switch was replaced.
I do believe the new unit has a longer, read closer to the thumb, horn button. This may be a way to know if you have a new or older switch.
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