Air Horn blowing fuse

Well had my first electrical problem I installed a air horn using the bikes horn wires to trigger the supplied relay to power the horn but what i failed to realize was that the supplied relay was rated for 80 amps so when you press the horn button that relay is trying to pull 80 amps on a 10 amp line smdh mind you it didn't blow right away it blew out of the blue causing no display or horn at all  they have the display marked as METER in the picture i supplied, the fuse B is marked in yellow with and arrow pointing at it for those who may run into this problem down the line :-) in red is the path it takes to the display from the battery the picture sucks but you can reference it to your pdf file or manuals picture, page 521 of the service manual oh and i replaced that relay with a 30 amp one and changed that 10 amp fuse to a 30 amp fuse

1st, you should never, ever, replace a fuse with bigger amp size, the fuse it's meant to protect the wiring by limiting the amperage to the wire gauge/circuit limit, overheating or burning a wire in a wiring harness will cause major headaches.

The main power supply to your new horn should use a dedicated/fused wire directly from the battery, the oem horn wiring should be used only to actuate the relay. The relay rating is for the contacts that supply the accessory, horn/lights/etc., the relay coil that pulls/closes the contact is usually low amperage and will never blow a 10amp fuse, check your connections.

Just out of interest, why do you need an air horn? I know the OE Silver Wing horn was legally adequate at best, but how often does anyone use a horn in normal day to day riding.

I had a Silver Wing for eight years and I don't think I ever used it, apart from occasionally checking to see it was working, and before presenting it for our annual MOT road worthiness checks. I've had my Forza for five years now and the same applies. I do accidentally press the horn button instead of cancelling the indicators/turn signals when I haven't ridden for a while and that’s it.

In fact I could go way back to the Seventies and say the same about the many motorcycle I owned, right up until I started riding maxi scooters in '96.

There is some old topics on here about fitting air horns and or those extra loud overkill locomotive horns. There seemed to be a fad for fitting them for a while, and problems were encountered with relays, or the horn compressor was too large to fit where the old Honda horn was.

Anyway have fun, I'm now in the mood to go to my Forza and test the horn loudness in my garage.

PS I don't think I will, unnecessary horn use is like loud exhaust noise, it just pisses people off.

zrx212 wrote:

1st, you should never, ever, replace a fuse with bigger amp size, the fuse it's meant to protect the wiring by limiting the amperage to the wire gauge/circuit limit, overheating or burning a wire in a wiring harness will cause major headaches.

The main power supply to your new horn should use a dedicated/fused wire directly from the battery, the oem horn wiring should be used only to actuate the relay. The relay rating is for the contacts that supply the accessory, horn/lights/etc., the relay coil that pulls/closes the contact is usually low amperage and will never blow a 10amp fuse, check your connections.

ok so the relay rating  refers only to the contacts and not the coil side thanks I have that side ng to the battery with a 30amp inline fuse I will change the horn circuit activation side back to the original 10amp fuse and recheck my wiring and thanks and to think I thought I was a pretty good electrical guy

Meldrew wrote:

Just out of interest, why do you need an air horn? I know the OE Silver Wing horn was legally adequate at best, but how often does anyone use a horn in normal day to day riding.

I had a Silver Wing for eight years and I don't think I ever used it, apart from occasionally checking to see it was working, and before presenting it for our annual MOT road worthiness checks. I've had my Forza for five years now and the same applies. I do accidentally press the horn button instead of cancelling the indicators/turn signals when I haven't ridden for a while and that’s it.

In fact I could go way back to the Seventies and say the same about the many motorcycle I owned, right up until I started riding maxi scooters in '96.

There is some old topics on here about fitting air horns and or those extra loud overkill locomotive horns.  There seemed to be a fad for fitting them for a while, and problems were encountered with relays, or the horn compressor was too large to fit where the old Honda horn was.

Anyway have fun, I'm now in the mood to go to my Forza and test the horn loudness in my garage.

PS  I don't think I will, unnecessary horn use is like loud exhaust noise, it just pisses people off.

Lol it’s a restore project and although loud enough I didn’t really like the beetle beep beep sound the horn small mounted tucked away in a nice spot behind the display and the relay went where the old horn was mounted a pretty clean install but I need to recheck my ground connection may have been loose and like another member advised to change that horn circuit back to its original 10amp setup

zrx212 wrote:

1st, you should never, ever, replace a fuse with bigger amp size, the fuse it's meant to protect the wiring by limiting the amperage to the wire gauge/circuit limit, overheating or burning a wire in a wiring harness will cause major headaches.

The main power supply to your new horn should use a dedicated/fused wire directly from the battery, the OEM horn wiring should be used only to actuate the relay. The relay rating is for the contacts that supply the accessory, horn/lights/etc., the relay coil that pulls/closes the contact is usually low amperage and will never blow a 10amp fuse, check your connections.

did as you suggested and also didn't realize it only happens when you START- close that what they call a limit switch in the left hand brake assembly, I had recently added a switch there to cut the head light on and off and i slid that brake assembly over and that connection was rubbing against the handle bar smdh but got it figured out LOL

ezed1 wrote:

Meldrew wrote:

Just out of interest, why do you need an air horn? I know the OE Silver Wing horn was legally adequate at best, but how often does anyone use a horn in normal day to day riding.

I had a Silver Wing for eight years and I don't think I ever used it, apart from occasionally checking to see it was working, and before presenting it for our annual MOT road worthiness checks. I've had my Forza for five years now and the same applies. I do accidentally press the horn button instead of cancelling the indicators/turn signals when I haven't ridden for a while and that’s it.

In fact I could go way back to the Seventies and say the same about the many motorcycle I owned, right up until I started riding maxi scooters in '96.

There is some old topics on here about fitting air horns and or those extra loud overkill locomotive horns.  There seemed to be a fad for fitting them for a while, and problems were encountered with relays, or the horn compressor was too large to fit where the old Honda horn was.

Anyway have fun, I'm now in the mood to go to my Forza and test the horn loudness in my garage.

PS  I don't think I will, unnecessary horn use is like loud exhaust noise, it just pisses people off.

Lol it’s a restore project and although loud enough I didn’t really like the beetle beep beep sound the horn small mounted tucked away in a nice spot behind the display and the relay went where the old horn was mounted a pretty clean install but I need to recheck my ground connection may have been loose and like another member advised to change that horn circuit back to its original 10amp setup

oh and here in the good old US of A there are a lot of rude Yahoos that have no respect for bikes so to get there attention this horn will do it