BMW R1200RT/R1250RT Forum

My bike is a 2014 R1200RTP Camhead, NOT LC! It had all of the police equipment removed except the side cases, radio box, and front and rear guards. The wiring was just snipped where the police lights and sirens previously resided. The left grip has a horn button, which does not work. And, there is a horn under the instrument panel. But, there is no wiring or connector to the horn.
I'm sure that someone much smarter has gotten the horn to work on their RTP. Could you please tell me how?

As an aside, I'd love to find out how to remove all the excess wiring without causing damage to anything else. With the second battery and all, there is a lot of extra wiring.

Our blood bike charity has recently acquired an RTP. The police wiring and equipment has been removed, but the dealer had to fit a separate switch and wiring to get the horn to work and pass the MOT. Why they haven't wired the horn directly to the horn switch is beyond me as to press the horn I have to virtually take my left hand off the handlebar.

1gewehr wrote: ↑Tue Feb 04, 2025 3:08 am My bike is a 2014 R1200RTP Camhead, NOT LC! It had all of the police equipment removed except the side cases, radio box, and front and rear guards. The wiring was just snipped where the police lights and sirens previously resided. The left grip has a horn button, which does not work. And, there is a horn under the instrument panel. But, there is no wiring or connector to the horn.
I'm sure that someone much smarter has gotten the horn to work on their RTP. Could you please tell me how?

As an aside, I'd love to find out how to remove all the excess wiring without causing damage to anything else. With the second battery and all, there is a lot of extra wiring.

I am in the process of doing this on my 2018 RTP.
My RTP came with the police siren and air horn. THw standard horn button activates the police air horn.
While this air horn is effective on the highway and very loud, it is not legal to use for civilians in my state.
I also want a less offensive horn to use for less than emergency situations.
To get the horn button to activate the standard civilian horn requires some programming. Or some say, a change in bike programing from police to standard configuration. Either way, the dealer would have to do that.

What I am doing is using the police buttons F1/F2 switch. Some are labeled differently. But this switch is located just below the horn button so it is convenient.
I located the circuit that is activated when pushing the F1 button. This circuit is found in the radio box. Its original intention is for the police radio, to activate the microphone.
I acquired a standard BMW civilian horn. I will attach a relay to that F1 circuit and then to the horn.
It will be nice having both horns.

My bike does not have the F1 and F2 buttons. And the sirens and lights have been removed with those wires cut. I DO have a civilian horn already in place. But it does not have the wiring to the horn.

From what I have heard, the dealer needs to program the bike so that the civilian horn is activated when the horn button is pressed. I have heard that this requires the bike be programmed as a civilian model instead of an authorities model.

OK, I now have a working horn!! The US spec RT-P is different from the ones sold closer to Berlin. Ours have the civilian horn and wiring in place. They just aren't connected. Kudos to user 'milos' on the LT forum for posting that.
After much searching, I found the connecter wrapped up in tape near the headstock. Once unwrapped and plugged in, the horn immediately worked!!