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Discussion Starter · #1 ·
I have read most of the posts on beefing up the wimpy stock horn so I have a pretty goood idea of the choices. I have decided to install the dual horn set up form the earlier RT's and have already ordered the parts from my dealer. But being the electrical idiot that I am, I have a few questions about the wiring and hope someone here can help me. I purchased the 2 pin repair plug and intended to splice that into the stock horn connector wire. But I can see that it is too short to reach from where the second horn will be mounted. Can I just add some wire to the repair plug and then splice into the stock horn harness using a posi-tap? any special issues re wire gauge or method of connecting the wire extensions to the repair plug? any polarity concerns? anyhting else to worry about??
In short, if someone who has already done this can give me detailed instructions I would be most appreciative.
Thanks in advance.
 

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I have an 07 RT and installed the dual 05 factory set up.
Somewhere I read this set up would not work on the 2011 & 12's.
Not sure which one you got, but check the harness compatibility out.
I got my answers from MAX BMW in Ct & New Hampshire where I bought the parts.
Think I spoke to Rose.
Good luck.
 

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I installed a set of used LT horns with very little wire soldering horn wire pigtail .
No relay just pluged into bike horn connector , no canbus faults . Just the sound of a real motorcycle horn not a weak a$$ scooter beeper .

Bob G
2011 RT
 

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Somewhere about 2009 the wire harness for dual horns went away. There is a real posibility that if you do wire two larger horns to the original circuit the computer that monitors excessive power flow in this circuit will cut it off. You need to use the original horn circuit to power a relay that gets its power from the battery directly (fused) and then goes to your new dual horns via the relay. If you search this list you will find threads detailing how to do this using some factory connectors for the trigger circuit wiring and setting up a relay. You need to do some research on this or have someone do it for you. Maybe some local help to do it together? Not easy to find space for the horns and a solid bracket. There are loud horns out there, Check Aerostitch. I suggest this one because it is cheap, smaller than the air powered ones that are a bit louder, thus easier to mount. I'm still looking for space to mount a five trumpet unit that plays La Cucaracha (http://www.amazon.com/CUCARACHA-Tru...TF8&colid=1YR2IVTAD5GH3&coliid=I3ARTH46TRKNEN)
Here is the link to a good horn.
http://www.aerostich.com/fiamm-freeway-blaster-horn.html
 

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beech said:
Somewhere about 2009 the wire harness for dual horns went away. There is a real posibility that if you do wire two larger horns to the original circuit the computer that monitors excessive power flow in this circuit will cut it off. You need to use the original horn circuit to power a relay that gets its power from the battery directly (fused) and then goes to your new dual horns via the relay. If you search this list you will find threads detailing how to do this using some factory connectors for the trigger circuit wiring and setting up a relay. You need to do some research on this or have someone do it for you. Maybe some local help to do it together? Not easy to find space for the horns and a solid bracket. There are loud horns out there, Check Aerostitch. I suggest this one because it is cheap, smaller than the air powered ones that are a bit louder, thus easier to mount. I'm still looking for space to mount a five trumpet unit that plays La Cucaracha (http://www.amazon.com/CUCARACHA-Trumpet-Musical-Horn-Kit-NEW/dp/B001EE0QXM/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=1YR2IVTAD5GH3&coliid=I3ARTH46TRKNEN)
Here is the link to a good horn.
http://www.aerostich.com/fiamm-freeway-blaster-horn.html[/QUOTEInstalled the x-tra hornin my '09 and the wring and mount was already there. Bought the Bike late may of 2009.
 

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I just added a second horn, Fiam Freeway Blaster from Aerostich. I had the extra plug taped to the horizontal cross piece so just spliced it in, the wires look to be about 16 guage. Just to be sure, remove left mirror and look down to see if you have the empty socket for a second horn.

r
 

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Discussion Starter · #7 ·
Thanks for the reponses. I am aware that I may have a Canbus issue by using the stock horn trigger wire to power both horns but I want to try that first. If I have a problem with the circuit shutting down I can re-wire with a relay. When I searched this list, it appeared that there were several people with 2010 and later RT's who had added the second horn and wired it off the stock horn trigger with no problems. This may be because the Canbus was apparently adjusted in 2010 to allow up to 10 amps vs the original 5 amps in earlier bikes.
So, where I could use some help is in the mechanics of the install - can I just connect the second horn wires into the stock horn harness using a posi-tap? any other issues to worry about??
Again thanks.
 

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I am also rather disappointed with the horn of my '20 RT. My daughter says it sounds "meep meep" (in a very sad way!)

I asked the local dealer about the possibility of adding the '05 horn, and they said that the only option would be to add another '10 horn. I would not know how to do it, but so far I have resisted the temptation to spend serious money on it (it is a BMW after all!)

Just my 2p worth.

Best regards
Sleuth
 

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itspossible said:
yes, just tap into existing wires, soldering would be better though.r
Here is the way to go if you want to be anal as I am. Yes, positaps are fairly good. Put a little dieletric grease in there to mush and seal as this is a wet area. But, here is the # of the factory BMW pigtail/connector that plugs in that horn connector harness side and has two 1' wires coming out for you to attach to your new horn harness. 833 0040 2344. I went to a relay with this set up to make sure all was okay. This is a connector that replaces the horn side of the connection and gives you a couple of wires to play with. The Stebil air horns take 28 amps to fire off. Fiamm stuff uses less. The BMW dealer who said there are no options on the newer bikes was lazy. He could easily make a couple of hundred bucks wiring in custom horns with a relay system. When you start doing this relay work, it is time to think about a fuse block for all your goodies.
 

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itspossible said:
yes, just tap into existing wires, soldering would be better though.

r
Indeed, simply tapping into the existing wiring is ok.
And soldering is definitely the best way, if possible finishing with heat-shrink tube, then wrapping
the splicing area and the added wiring with a protective tape such as 3M Temflex.
 
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