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Horn cable disconnect

3K views 13 replies 7 participants last post by  ccramerusc 
#1 ·
I'm in the process of installing a Stebel horn on my F 800 GT. My question is how do you disconnect the connector that attaches to the horn from the horn itself? Or on installing a Stebel horn do I cut and splice the cable to the horn further up line and splice it there to the new horn wiring harness?

Thanks,

Chuckerconnie
 
#2 ·
A Stebel will draw at least 15 amps, so you'll need a relay. If not it will burn out the original switch. I would cut the wire from the switch to the original horn and run it into the 85 terminal of a relay. Then attach the wires that came with the horn to the 87 terminal. Attach the 30 terminal to the battery with a fuse (I ran mine through my fuzeblock), and the 86 terminal to ground.

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#3 ·
When you suggest "cut the wire from the switch to the original horn" where do you suggest cutting it, at the horn button or down where the wiring terminates on the horn itself? If at the horn itself would you cut the wire right at the connector on the horn or a few inches back from the horn connector? I assume I need to do some splicing somewhere. Does it matter which wire to the existing horn goes to the 86 terminal and which to the 85 terminal?

Thanks for your response.

Chuckersconnie
 
#4 ·
The bike does not have a wire from the horn button to the horn. The horn button is an input to the ZFE module. When the ZFE senses the horn button closure it sends power to the horn. You could replace the horn with a relay coil but there is no guarantee that the ZFE will be happy with the current draw difference. Assuming that it is ok then the best way to wire in the relay coil would be to disconnect the stock horn and source a mating connector to plug in. The mating connector would bring power and ground to the relay coil. Power for the new horn would come from the battery via the relay contacts.

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#5 ·
Yes, it has to go through the computer, so cut it just as it gets to the horn. That way there will be voltage to trip the relay. On my ST I removed the stock horn and cut the wire just as it got to the fitting. I then ran that wire back up to the relay. My relay is attached with the bolt that holds the battery down.

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#7 ·
Thanks for all your input guys! I appreciate it. But my initial question was how do you disconnect the BMW connector to the horn from the horn? Other than just cutting the wires, which I gather doesn't matter which wire goes to the 86 connector and which goes to the 85 connector, what is the trick or technique to removing the connector from the horn itself?

Thanks,

Chuckersconnie
 
#8 ·
It's been 6 years since I did mine, so I went into my spate parts bin and found my original BMW horn. As you can see, I just cut the wires. Green was the power in, so that's the one you want to run to the relay.


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#9 ·
Go on Cramer stop teasing the OP un clip the cut wires from the horn and tell us all how you did it (looks like the indicator socket type to me)
 
#11 ·
The retaining clip on the horn connector isn't as obvious as it seems but it is there. Once you depresses the connector will slide right off. If anyone knows where to get a horn side connector you'd be in business without having to cut anything. You could just use that connector to wire into your relay. it's always nice to keep things stock and not cut anything.

On the same note, if anyone knows where to find the bike side connector for the horn I would love to know. I've built a few harnesses that connect to standard BMW horns and I've always had to use some "borrowed" bike-side connectors on the new harness to connect to the stock BMW horns that I've added.

Searching eBay finds a lot of connectors for BMW cars and some that actually look like the horn side connector but I've never found anything for the bike side connector. Any suggestions?
 
#14 ·
It's been many years since I did this to my ST, but if i remember correctly, I cut the wire coming from the switch to the original horn and attached it to a new relay which I mounted between the air filter and battery. Then I ran a much larger wire from the relay to the horn. There is obviously another larger wire running from the battery (I use a fuzeblock instead of the actual battery) to the relay. I don't remember what i did with the ground wires. Something goes to the battery negative terminal (my fuzeblock), but I'm not sure if that was from the relay, from the horn, or if those two are spliced together.
 
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