Wiring the Horn Relay

Honestly, part of me wishes I had just ordered a horn wiring kit online.  If you don't have any wire, any crimp connectors, or any heat shrink tubing, you will end up spending some serious money trying to wire this.  Although, it can be argued that without doing everything custom for this bike, it wouldn't have come out so neatly.  After going in circles without the wiring diagram, and getting rough drawings of what other people have done, I was still left trying to figure it out myself for the most part.  The first thing I really spent a lot of time trying to figure out, was which wire in the harness was the horn switch.  I spent hours and hours pulling apart the block connection that leads to the left hand-controls, and using a multimeter trying to figure out which wire does what and was soooooo confused.  Nothing was working the way I would have expected it to.  I needed to find the wire coming back from the switch that signaled to turn on the horn.  But then I realized that the power wires for the horns are coming from the hand control wire-harness.  Meaning there is no extra wire somewhere signaling that the switch is closed.  So suddenly I was looking at cutting into the wiring.  Somewhere on the net, it said I should tap into the green wire in the headlight.  But I just couldn't figure out how that would make the relay trip when I pushed the horn button.  I was stumped.
After getting an ear-full about spending so much time on the bike, and no time studying for my classes, we went out to eat sunday night.  And I swear I was listening to her, I honestly swear that I was, and suddenly that dim little lightbulb turned on in my head.  I don't need to cut or splice any wires at all.  All I need to do is make a wire with a male spade at one end and female spade on the other, and connect one side of the relay coil to one of the positive wires for the horns.  Problem solved.  When I press the horn button, power goes into the horn wires, which is re-routed to the relay coil, causing the relay switch to throw, sending power to the new horns.  Bingo.  No cutting, no splicing, and no messing with the fuse block, or any other wires down there.

What you will need:

1.  SPST relay that came with my horn, and which you may need to purchase yourself if your horns did not come with them. 

2.  Roughly 10 feet of 14 ga red insulated wire and 10 feet of 14ga black insulated wire.  I got the stuff at the automotive store that has more of a rubbery flexible insulation than the cheap stuff with hard plastic insulation.

3.  One ten amp regular sized blade fuse.

4.  One inline weatherproof fuse block that holds a single blade fuse

5.  Heat shrink tubing

6.  Various crimp connectors.  One suggestion here:  just by the regular old kind of connector.  At first I got some fancy crimp connectors with the heat shrink tubing as part of the connector, and these ended up failing me big time.  When I shrank the tubing on the connector, it released some kind of residue into the joint which caused half of the connections to fail.  I literaly tested continuity between one end of a connector and the other end of the connector(with the wire already removed) and there was no continuity.  Whatever that white residue is, it really fouled up my connections, and I had to start over.  

This is the basic layout of a SPST relay:
                                  ________________
                                  |          ___            |
                                  |           87            |
                                  |  | 86           85|    |
                                  |                          |
                                  |           |              |
                                  |______30______ |

Do not laugh at my lame drawing of a SPST relay.  Just run the connections in the way I ran them in this photo:

This is where I located everything:

 I tucked the relay and fuse next to the airbox behind a little plastic cover.  I was really surprised at how well this worked out.  You can also see where I connect to the original positive horn lead, and that the negative is taped off to prevent corrosion. 

Here, I have put the plastic cover back over the area completely concealing the relay and fuse.

 

Here you can see how I followed the main harness all the way back to the battery.  And I'm sure you can figure out how to attach the wires to a battery, but here's my photo, just cause I took one, and I might as well put it in here:

I think that about sums it up...