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Fit Additional Horn to 2010 R1200RT


Doublebassman

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Doublebassman

Hi there, I've been following various threads about adding an additional horn to the RT. According to the Haynes manual there is wiring in place for two horns (terminals 43 and 56 on the ZFE Central Electronics Unit). I've bought the appropriate horn connector lead for the CANbus system, and my bike already had an additional horn installed by the previous owner, but not wired up.

Does anyone know where this connector is? I've found what I originally thought was the connector (see photo) but this is essentially a blank which goes over a male connector (I think I'm looking for a female connector). Also, I'm wondering if the connector in the photo may be to do with the DWA 6 alarm system.

Many thanks, Chris

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Your photo isn't working for me, but it may be the NAV power connector you're seeing. My 2013 doesn't have the second horn connector, and I'm thinking your 2010 may not either. I bought hi and low Hexhead OEM horns (like I had in my '06) and wired them both to the single connector. They work great.

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Attachments don't work on this forum, Chris. You must upload the photo to a photo sharing site (imageshack, photobucket, etc.) and insert the photo's internet address in your post. See ***HERE*** for more info.

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Chris, the Haynes manual wiring diagrams for the '10 on RT lies - not for nothing are they frequently referred to as 'the haynes book of lies'.

The camheads were only ever fitted and wired for one horn. Not being able to view your photo, I'd guess the connector you found is the power feed for the nav system.

Although the second horn output is not wired, that pin output is still active on the ZFE. Slightly confusingly the output that is used is referred to as Horn2 (pin56) and will generate an error if disconnected - but the configuration does not monitor the pin 43 output.

It is possible to use the output from pin 43 to drive a second horn, but you would need to source a connector insert for the ZFE connector and connect an earth into the existing loom (or direct to the battery). With care you can thread a new wire in the loom to both an earth junction and the ZFE so it looks as original as possible.

I did actually do this to my own RT - just wanted it to look original and I had the parts to hand.

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Doublebassman

Hi - thank you so much for this information. I must admit I was beginning to wonder if the Haynes Manual was telling the whole truth!

I would very much like to wire mine as you have wired yours, and this would also negate the need to install a relay.

Would you mind providing some more info for me? In particular I'd like to know where I can find the ZFE unit, what connector I would need and basically some step by step instructions. I'm totally new to the world of BMWs and CAN-bus, so any adice you can provide to a) help me achieve this and b) keep my RT as original as possible would be great. Thanks again, Chris

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Doublebassman

Blind Squirrel, John and Lee,

 

Thanks for your suggestions and also for the link. John, I'd actually seen this and did think of doing this myself.

 

However, I think it would be a great project to tap into that spare horn feed from the ZFE. It would almost be in defiance to BMW having removed the wire from the loom on the 2010's. I'll try and find out more info, but so far there appears to be no info anywhere on the internet on how this is done.

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If you can find a mounting place for a second low or high horn, it's seriously dead-easy to just tap the second horn into the single horn connector and you've got a good 2-tone blast sound.

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Doublebassman

Thanks John. The second horn is already fitted onto the spare mounting bracket on the left hand side just incide the fairing. So I'm just waiting to hear from someone who can help me connect to the second horn pin of the ZFE.

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  • 7 months later...
Doublebassman

A brief update on my additional horn project...

 

I obtained a spare ZFE connector plug from a scrapped RT and used this to provide a donor connector pin to add to my existing ZFE connector. As the horn feed uses a 0.75mm2 lead I used a connector pin from the lower ZFE donor connector (the wires from the upper one are much lighter, typically 0.35mm2) and connected this to the pin for the other horn output (pins 43 and 56 feed the horns).

 

I then located the main earthing point in the loom and connected my new earth lead to this point. This gave me a new supply to feed the additional horn.

 

I decided to splash out and treat myself to a pair of brand new BMW older style trumpet horns as fitted to the earlier RT's. The part numbers are in this forum somewhere, but if anyone needs them I can provide them. Not cheap, but I was quite keen to use OEM parts.

 

Fitted the new horns, taped up my new loom addition and put everything back together.

 

I now have a very loud original BMW twin tone horn properly wired into the ZFE unit as if it had been installed by the factory!

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A timely discussion. This morning a woman next to me in her mercedes, I could look in and see her reading texts, tried to mopver into my lane, and did not even hear my pissy little stock horn. We were moving slowly enough that I was able to accelerate a bit and clear myself. Next time a more lively horn will surely cut through the fog.

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A brief update on my additional horn project...

 

I obtained a spare ZFE connector plug from a scrapped RT and used this to provide a donor connector pin to add to my existing ZFE connector. As the horn feed uses a 0.75mm2 lead I used a connector pin from the lower ZFE donor connector (the wires from the upper one are much lighter, typically 0.35mm2) and connected this to the pin for the other horn output (pins 43 and 56 feed the horns).

 

I then located the main earthing point in the loom and connected my new earth lead to this point. This gave me a new supply to feed the additional horn.

 

I decided to splash out and treat myself to a pair of brand new BMW older style trumpet horns as fitted to the earlier RT's. The part numbers are in this forum somewhere, but if anyone needs them I can provide them. Not cheap, but I was quite keen to use OEM parts.

 

Fitted the new horns, taped up my new loom addition and put everything back together.

 

I now have a very loud original BMW twin tone horn properly wired into the ZFE unit as if it had been installed by the factory!

 

How about some pirctures? This sounds like a worthwhile effort. I'm not too keen on just spicing into the wimpy wire used for the single horn setup (yes, I know I could use a reley).

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The two horn setup without a relay worked fine on the 2005RT I owned and it's working fine on the 2012RT. Has anyone else had a problem using two horns without a relay?

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The Rocketman

I followed the instructions on this site to add new horns to my '09 RT without a relay. Removed the stock, single, wimpy horn, found the 2nd horn power lead taped to the frame, and bought this:

 

2003 R1150RT horns off Ebay for $25.00!

46717675209 ISA screw $ 2.00

61331459545 Cage Nut $ 1.14

 

61338381271/61337655881 (old p/n) Low pitch 420Hz $ 63.55 (dealer price)

61337655882 High pitch 510Hz $ 53.37 (dealer price)

 

I called Bosch directly and confirmed horns were identical, just part numbers had changed over the years. One bracket was backwards. Easy fix, 10 minute job, and the results were outstanding.

 

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I followed the instructions on this site to add new horns to my '09 RT without a relay. Removed the stock, single, wimpy horn, found the 2nd horn power lead taped to the frame, and bought this:

 

2003 R1150RT horns off Ebay for $25.00!

46717675209 ISA screw $ 2.00

61331459545 Cage Nut $ 1.14

 

61338381271/61337655881 (old p/n) Low pitch 420Hz $ 63.55 (dealer price)

61337655882 High pitch 510Hz $ 53.37 (dealer price)

 

I called Bosch directly and confirmed horns were identical, just part numbers had changed over the years. One bracket was backwards. Easy fix, 10 minute job, and the results were outstanding.

 

Unfortunately, the power lead for the second horn was removed in 2010 and later models.

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What we all need to see is a photo of where the new wiring is connected to the ZFE.

It is under the steering head. It moved from my '09 hexhead's 2-connector position in the left side of the nose to my '12 camhead's central between-the-forks position.

 

In the photo below you can see the large zip-nut and original horn bracket (black plate) from which my '12 RT's two FIAMM horns hang:

 

CIMG2713.jpg

 

I picked up a two-wire connector pigtail corresponding to the horn's connector and plugged it right into the bike's horn harness, then ran the wires to a relay to trigger delivery of power to the two FIAMM horns directly from the battery:

 

Horn%20connector_zpsjg9rhkhp.jpg

 

I've always gone for a relay for two reasons:

 

While the very small OE wiring can handle a short honk, I'm not convinced it will do so when the horn is held on for any significant length of time (not to mention the voltage drop across the small wires -- I want as much voltage and current reaching the horns to make noise as possible!).

 

I am also aware that the ZFE has the ability to shutdown a circuit if it draws too much current, and the ZFE's thresholds aren't that high. I do not know whether that would be a problem with the horn circuit powering two strong horns, but I didn't want to find out by having the ZFE shut off the horn at a moment I needed it.

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