Stebel Horn on a 1600

[ringadingh]

In this post I am going to discuss two different scenarios for wiring a Stebel horn on a 1600 Nomad. This may also apply to the 1500’s and the 1700’s but I don’t have wiring diagrams for those so I make no guarantee that my directions will be correct for those models.

Do not attempt to connect a Stebel Nautilus horn directly to the stock horn wires! You WILL blow the 10 amp fuse! DO NOT replace the 10 amp horn fuse with a larger fuse in an attempt to use the stock wires. You WILL eventually burn out the stock switch and/or wiring.

Parts required:
30 amp SPST automotive type relay, such as the BOSCH PART NUMBER 0332-019150
20 amp inline fuse
12 gauge stranded copper automotive wire
16 gauge stranded copper automotive wire
Spade connectors, male and female

Scenario One:
Wiring a Stebel Nautilus using only the ground wire which connected to the stock horn.

Scenario Two:
Wiring a Stebel Nautilus using both wires which connected to the stock horn.

Before I start I will discuss the wiring of the stock horn and horn switch. I believe that a basic understanding of this circuit is needful for the successful wiring of a replacement horn.

Here is a simplified wiring diagram taken from the Nomad 1600 Service Manual:



Notice that 12 volts is supplied directly to the horn from fuse #2 which is located in the Junction Box. This wire is hot whenever the ignition switch is on.

The other wire on the horn connects to the horn switch. When the horn switch is depressed the circuit is completed to ground and the horn will sound. The fact that the horn switch provides a ground rather than providing 12 volts to the horn is the important fact here.

You need to determine which of the stock horn wires are hot and which is ground! This can be done by using either a voltmeter or a test light. Disconnect both wires from the horn and test them. Mark the wires so that you will know which is hot and which is ground. You will need to know this later.

Now, on to the good stuff.

Scenario One

Stebel Nautilus replacing the stock horn while using only the ground wire from the original horn.

Wiring diagram for scenario one:



Disconnect the negative wire from the battery.

Disconnect both wires from the stock horn. Tape up the connector end of the hot wire so that it cannot touch anything and short out. This wire will not be used in this scenario.

Connect one end of the inline fuse to the positive terminal of the battery using 12 gauge wire. If you have installed a fuse block and plan to use it to provide power you can skip this step.

Prepare a wire to connect from the inline fuse to the relay. Use 12 gauge wire to reach from the fuse to the relay. You want to make a Y connection on the end which will attach to the relay. You can use 16 gauge wire for the short leg of the Y. Attach one end of both the 12 gauge wire and the 16 gauge wire into a female spade connector. Attach another female spade connector on the remaining end of the 16 gauge wire. (This 16 gauge wire will provide power to the coil of the relay while the 12 gauge wire will provide power to the horn through the relay.)

Connect the 16 gauge wire onto terminal 86. Connect the 12 gauge wire onto terminal 30. Connect the other end of this wire to the inline fuse or to a 20 amp position on a fuse block. Refer to the wiring diagram.

Run a 12 gauge wire from terminal 87 of the relay to the positive terminal of the Stebel horn. (You will probably have to remove the fuel tank to do this.)

Run a 16 gauge wire from terminal 85 of the relay to the GROUND wire which was on the original horn. Use a male spade connector on the end of this wire which will connect into the existing female connector on the horn wire. Do NOT connect this wire into the existing HOT wire.

Connect a 12 gauge wire from the negative terminal of the Stebel horn to the nearest frame ground. (The top crash bar bolt is a convenient place. You may wish to use a ring terminal on this end of the wire.)

Double check your wiring and connections.

Replace the fuel tank if you removed it.

Reattach the wire to the negative terminal of the battery.

Try the horn. (You may want to move the bike outside to do this. )


Scenario Two

Stebel Nautilus replacing the stock horn using both original horn wires to activate the relay.

Wiring diagram for scenario two:



This scenario has just a couple of differences from scenario one. There will be three wires run under the fuel tank going from the relay to the horn area, rather than only two as in scenario one.

First, don’t make a Y connection on the end of the wire which comes from the inline fuse and connects to terminal 30 on the relay.

Second, run a 16 gauge wire from terminal 86 on the relay to the positive (or hot) wire which connected to the original horn. Use a male spade terminal on the end of the wire connecting to the horn wire.

Everything else is wired the same.

Good Luck!

Yellow Jacket