Relay for horns? Horn wiring behind headlight?

[LCS249]

Hi all,

I purchased a set of Stebel Magnum horns (136 db) and installed them.

But apparently one is supposed to use a relay (included).

I've got a diagram (which is like Greek to me) and I'm checking here to see if folks know for sure whether the horn wiring is behind the headlight?

thanks, LCS

[TopCatGr58]

Hey there LCS,

The reason for the Relay is because those horns are going to draw lot more power than what you'll get thru the OEM horn wires!

Here's what I did. Connect a tap wire to the AUX terminal + screw and run it up to where you want to put the relay, usually under the gastank. The relay should have 4 wire connectors. Hopefully your diagram show the HIGH power side which is the side that is thrown by the relay. That's where you want to connect 1 end of the 12 volt tap from the AUX. You connect the other connector to both of your horns + terminals. Usually the horns will be grounded by the mounting brackets to the frame.

Then connect 1 of the 2 yellow wires from the old horn to the + terminal that throws the relay switch, and then connect 1 of the 2 pink wires to the (-) side of the relay throwing circuit terminal.

So...now when you hit the horn button, the pink wire which runs to the handlebar switch will be grounding, this will provide power thru the yellow wire to THROW the relay, this will then provide the connection/power from the Aux term wire thru the relay to the horns for a full blast!!
T.C.

[John]

Most Bosch style relays, like the small, plastic ones used for the horn, have a schematic diagram printed on them, along with the terminals numbers. The numbers are 30, 85, 86, & 87. These numbers are standard to all relays of this type. The way I wired mine is like the method TC described. From the AUX terminal (terminal assy is what it is called in the Clymer manual) run a 12 gauge wire to the #87 terminal, and then continue the wire from terminal #30 to the horns. That will complete the controlled circuit of the relay. Now, using the brown wire that was going to the horns, route it up to your relay, and attach it to the #85 terminal, and using the pink wire that feeds the horn button, attach that wire to the #86 terminal. That will complete the controlling circuit of the relay. Now when you depress the horn button, you will complete the ground, and energize the relay. That will close the contacts in the relay, and send power to the horns. Also the horn wiring does not go through the headlight bucket, it runs with the turn signal wiring under the tank, and there is are two connectors near the front of the tank. One of the connectors carries the power to the switches, and the other carries power to the components from the switches.

[MaximPhil]

Just to add to the above. I recently added "wake the trucker" horns too. With the assitance of Jim & Wayne. It went much better when Wayne provided the plug with wire tails for the relay. Napa or similar will have one. A couple of tiewraps work well to hold the relay to the frame under the tank.
Maxim Phil

[LCS249]

Thank you T.C., John and MaximPhil,

Here's a link to the diagram Safemoto sent me:

http://www.bikerhiway.com/installinf...um_install.pdf

The diagram shows the numbers John mentions.

I very much like the idea of using the AUX terminal + screw, T.C., as well as getting a plug with wire tails. Those two ideas save a considerable amount of stress.

best, LCS

[Axel]

Option

The only advantage to wiring it direct to the battery with a fuse holder would be to avoid that extra currant being drawn through the fuse box and maybe melting some old wiring

[wa407mpp]

new air horn

If anyone is interested Aerostich is now selling a new compact air horn made especially for bikes, that puts out 139 decibels, for only $37.00. It is supposed to sound like an 18 wheeler or a large ship horn.

[Axel]

Got my magnums on last weekend . I am impressed . Deafening in the garage ! Installed to the original mounting threads although I had to drill out the supplied brackets on one end . Wired direct to the battery with the supplied relay and a fuseholder . They rock so much more than the 26 yr old horns .

[Macamon]

I'm confused . I looked at the schematic for my bike and it shows one wire from the horns going to the button, which grounds when pressed. I put a tester on one wire, turn on the bike and it's hot. Change wires, turn on the bike and that one's hot too. What up? One of them should give continuity to ground when the horn button is depressed, why would both wires be hot?

[Macamon]

Oh yeah... And do the Hella horns need a relay or will they work off of stock horn juice?

[Axel]

What I did

You should have a tan wire and a pink wire going to each horn . One of these sets is what you plug into the trigger terminals on the relay nos. 85 and 86 ( tape off the extra tan wire and pink wire ). The power wire that you install with a fuse goes to terminal 30 (silver in color)and to the battery for ease . The no. 87 terminal supplies the power to the horns (split with a scotch-lock for two) . You also run a ground to each horn. Use a relay for full horn effect and no chance of melting your OEM horn switch .

[Macamon]

Thanks for the input. I guess I will need to acquire a relay.

[Axel]

Np

I used a 30 amp four terminal relay . There is another thread here somewhere you can search for that has the proper name for it .I also used a 20 amp fuse .

[Axel]

1 years after

And one season later , one horn is dead and drawing a lot of current . I have it unhooked and the remaining one is loud but not two tone . So that is my experience with Stebel magnum .
They actually arrived with cracks in the plastic that I superglued and more cracks have come with being on the bike . A "cheap" fix is going to cost me in the end I guess (AGAIN) .

[TopCatGr58]

Hey Axel,

Sorry to hear that! I had put some inexpensive horns from the local auto store several years ago. I had wired them with power directly from the AUX terminal thru a relay triggered by the OEM button/wires. One of them wasn't working, and the other seemed a bit muted!

I saw that there was a "tuning" screw encased in plastic or rubber, so I dug/cut until I could access the screw and started "screwing" around with it while hitting the horn button, and it came back to life, and I was able to get it back to it's loudest level.

So...you might try playing with the adjuster screw to see what you can get it to do!
T.C.