I recently install the Stebel Nautilus Compact Horn. (Hey, I'm small, so they gota know I'm there, right! )

The horn circuit is a 15 amp circuit so I disconnected the old horns so I would not be popping fuses evertime I hit the horn. (It sounded great until I started blowing fuses. )

But, I suspect because the Stebel draws 18 amps that I will still blow the 15 amp fuse. If so, can I replace the 15 amp fuse with a 20 amp fuse without any worries?

Will the wires hold up? I used 12 gauge wire for the new horn but I believe the old horns, which I tapped into, are 16 gauge wire. I know the 12 gauge are fine but what about the 16 gauge, Is this a bad move?

Thanks,
ChrisO

 

Did you use the relay? From what I've read (I'm looking at the same horn or maybe the TM-80 Magnum) you need to install the relay to prevent just this

 

Oh yeah, and in case you're not sure what the relay does (I wasn't), you wire the relay to the battery and the horn, then the horn switch to the relay. That way, the std wires only have to handle enough power to switch the relay, then the relay and the new (thicker gauge) wires carry the higher current from the battery to the horn.

Did that make any sense? I have a tendancy to babble

 

No you are making sense. So if I add the relay can I keep the old horns as well?

ChrisO

 

You know, now that I think of it, the directions were not very clear about the relay. They made it sound like you only need to use the relay if you don't have existing horns, so I didn't use it.

I will go back and install the relay.

CO

 

Yes - you can keep the factory horns if you use a relay to power the new horn.

The magnetic switch in the relay only draws a few milliamps of current, so it's essentially adding no load to the stock horn wiring.

 

I'm not certain, but I think you kill both std horns. I think, since the relay wires straight to the horn switch, there's no convenient way to keep power going to the std horns unless you start splicing wires.
It might help to Google it. I've found ALOT of stuff on some of the motorcycle sites about these horns and you might get lucky and find a How-To

 

Damn I type slow...

 

If the directions aren't very clear, here's the basic wiring scheme using a standard Bosch Single-Pole / Double-Throw (SPDT) relay. You actually only need a single-throw relay, but the double-throw relays can be used as a single-throw by leaving one terminal disconnected, and they're the same price, so most applications include the double-throw version whether it's needed or not.

If you look at the relay, the terminals should be marked 85, 86, 87, 87a, and 30. 85 and 86 are the terminals for the magnetic switch, and 30 is for the 12V input wire.

When the relay is NOT energized, 30 is connected to 87a. When the relay IS energized, 30 is connected to 87. So, the correct wiring assignments are:

30 - Heavy fused wire directly to battery
85 - small wire, tapped into the factory horn wire
86 - goes to ground if the factory horn wire is +12V with the horn button pressed, or goes to +12V if the factory horn wire is grounded when the horn button is pressed. (I don't know whether the factory horn switch is on the power side or the ground side of the circuit).
87a - not connected
87 - +12V output to your new horn.

85 and 86 can be reversed, since the magnetic switch in the relay isn't polarity-sensitive.


So what happens is that when you press the horn button, the circuit across the magnetic switch (85 & 86) is completed, which then connects the battery (30) to the new horn input (87).

Hope this helps,

 

Sounds great! No pun intended.

I do have a double throw relay that came with it. It does explain how to install it but it gives directions for only one type of configuration.

The info you are providing will be very helpful. I will give it a try tomorrow.

ChrisO

 

I put a pair of the full size ones in my Subaru and also kept blowing fuses. Rigging up a harness and using relays is the ticket. You'll want to fuse the new power leads going straight to the battery, with the stock horn wire used to trigger. Trust me, it's worth it!! I've got a vid and sound clip I can share if you want

 

I've got a 20 amp inline fuse that will work perfectly. I just have to rig everthing up.

The relay I have does not have a 86a and there are 2 numbers, 30 & 87, next to the lower pole. So I would assume 30 is the + from the battery and the top 87 goes to the + on the new horn.

The only confusion is; 86 goes to either ground or, and this is where I'm not sure, the +12v side of the battery, which would mean I have two + connections from the battery which does not sound right??

It that correct?

 

Yes - it's common to have two connections on the relay going to +12V. One connection is the heavy-gauge lead to the battery, and the other is a smaller-gauge connection to one side the magnetic switch. Then, the other side of the magnetic switch would tap into the factory horn wire, assuming the factory horn wire goes to ground when the horn button is pressed.

If the factory horn wire goes to +12V when the horn is pressed, then the other side of the magnetic switch in the relay would need to be wired to ground instead of +12V.

If you do need two of the relay terminals to be connected to +12V, you don't have to run two separate wires all the way to the battery. You can run a short wire from one terminal to the other, and then the fused heavy wire from 30 back to the battery.

 

I'm planning on installing a Nautilus as well. I have fabricated a bracket to bolt to the two studs in the passanger side cowl area but haven't yet had time to do anything else. I plan on tapping the factory horn for a turn-on lead to the Nautilus an running a fused power connection from the fuse box. I took a look at the Bentley manual and it looks like the horn switch is on the +12V side so one wire will tap the stock horn power and the other will go to ground.

 

You guy's are great!

I hooked everything up today and it appears to work fine. I will keep my eye on it and report back if there are any complications.

I also hooked up the existing horns for a 4 tone sound.

Just for your info I ended up running the #86 leg to ground and I also included a 20 amp inline fuse off the battery.

The only thing that might not be good is the horn is located on the outside of the ABS module compartment and may get a lot of heat. It just would not work right if I placed it inside the ABS compartment.


CO

 

Mine worked fine inside the ABS compartment before I moved them to the front OE location. This required removal of the front bumper cap - not a major issue - you may be able to fit the Stebels in the OE horn location up front for a more forward-projecting sound.

The sound from the horns in the ABS compartment "vented" out the vent - I was careful to angle the horns so no water collected inside.


IMHO, the outside of the ABS compartment will get mighty hot.

 

Reminds me of the time I hooked up a set of "18-wheeler" horns to my Mazda Protege. I was almost broadsided by some idiot even though he heard the horns. When I asked him what his problem was, he said he was looking around for the semi!

 

Nyaah, with these they look around for the MG or Jag...