Horn relay question

[Goman]

Can someone with a manual tell me if there is a relay in the horn circuit of my '04 Rockster? I want to install an air horn that draws mucho or so amps and don't want to melt the wiring. The connector on the existing "feeble" horn looks as if the wires are mighty small! TIA

[NoRRmad]

There is a relay, but it's not for "mucho" amps. I've inquired about a larger OEM one, but nobody seems to know of one. As you note, the wires are small, and would need to be replaced or bypassed. It's probably simpler to buy an appropriate sealed relay and fuse combination and just wire the whole thing yourself. Use the existing horn wiring to trip the new relay.

[Goman]

Well ok, thanks for that. I disconnected the horn and removed it but after looking at it, decided to put it back on until I buy a relay and fuse. There is 12V on the connector when I turn on the key and press the button but the damn thing does not work at all now! Tried WD 40 on the connector but no luck. I guess it died when I cursed it last time. Wasn't worth a S--t anyhow.

[lionlady]

When I got the Stebel Nautilus Compact horn, it came packaged with a relay. Unfortunately after installation, the relay died within about 4 months. Replaced it with a good Radio Shack relay and it the horn has worked ever since.

Regarding an OEM relay... I'd bet money that BMW doesn't produce any sort of electrics themselves, so why not just get a relay from a known producer of electrical stuff?

P

[NoRRmad]

Well ok, thanks for that. I disconnected the horn and removed it but after looking at it, decided to put it back on until I buy a relay and fuse. There is 12V on the connector when I turn on the key and press the button but the damn thing does not work at all now! Tried WD 40 on the connector but no luck. I guess it died when I cursed it last time. Wasn't worth a S--t anyhow.

I think there's an adjustment screw on the horn that's very sensitive. These horns make their sound by using the tiny movement of the diaphragm to inturrupt the DC voltage, and just removing the horn can probably warp things enough to need a readjustment.

[stilldking]

Regarding an OEM relay... so why not just get a relay from a known producer of electrical stuff?

The problem is the stock wiring. It's waaay too small to handle the amperage a Stebel (or anything aftermarket for that matter) would require.

JC

[lionlady]

Regarding an OEM relay... so why not just get a relay from a known producer of electrical stuff?

The problem is the stock wiring. It's waaay too small to handle the amperage a Stebel (or anything aftermarket for that matter) would require.

JC

HUH? My Stebel horn IS wired into the stock wiring, along with my AutoCom, extra lights, etc. etc. No problems yet.

Only recently installed a BlueSea fuse block, and all the electronical farkles are now wired thru that.

P

[riceburner]

Regarding an OEM relay... so why not just get a relay from a known producer of electrical stuff?

The problem is the stock wiring. It's waaay too small to handle the amperage a Stebel (or anything aftermarket for that matter) would require.

JC

Heavy enough to power the relay throw though.

[boxermania]

Gentlemen

The wiring to the horn is not the problem, in most cases, it is the fuse, which of couse is there to protect the wiring. (Also need to find out if the fuse serves more than one circuit, as that is additional load on the fuse)

The easiest way to find out, at the expense of a fuse is to temporarily wire the new horn(s) to the original wires and try it out.....if the fuse blows you are drawing more current than the circuit was designed for and you'll need a separate relay, if not, you are home free.

Do test it with a two or three second power application..........

[kiteman]

Hey Lion-
I am wondering if you know what sized/shaped bracket you used to mount the stebel....There are quite a few options at twisted throttle, and I am trying to only order from them once. Thanks!

[lionlady]

Hey Lion-
I am wondering if you know what sized/shaped bracket you used to mount the stebel....There are quite a few options at twisted throttle, and I am trying to only order from them once. Thanks!

ORDER the bracket??? We bought an angle bracket from Home Depot and used that at the OEM horn attachment point. Needed something that got the SNC out from between the fork legs a bit more.



P

[kiteman]

Yeah, yeah, I know it's pathetic ordering a custom fitted mounting bracket, but I'm at a point in my life where it makes more sense to spend 20 minutes researching something on the internet , dropping the eight bucks on the Amex and have it show up on my doorstep four days later than drive 15 minutes to HD, spend 15 more minutes searching for the piece I'm going to jerry rig, 15 back..... you get the idea. The days of making and mounting surfboard racks to the side of my Honda 350rxl have long since passed ( : Thanks for the great photo's!