Why would my horn blow my fuses?

[tedrogers]

Hi all,

I've noticed a strange electrical problem when I press my horn it blows the 10A fuse in the back on the right under the side panel.

The brake light and horn are on the same circuit, so obviously pressing the horn whilst out on the bike is not ideal as it kills your brake lights!

Really hard not to press it too, especially when there is a nob head about to knock you off. And sometimes you can press it by accident when canceling indicators. Anyway, I digress...

I have a pair of Motrax Hootaz fitted in series to the main horn (which is rubbish). The Hootaz have been working great for over a year, and now all of a sudden they are blowing this fuse all the time.

Does anyone know what would cause this problem, or experienced it themselves? And more over, does anyone know how to fix it?

Thanks for any advice.

 

[huxy]

The horn is probably taking enough current at startup to blow the fuse. When something takes that much you should put a relay in and then a fused connnection just for that thing back to the battery. The horn line then switches the relay on and off, but carries very little current.

This guy has pictures and words for your horn.

My Horn Upgrade Project: Installing Motrax Hootaz - Triumph Sprint Owners Club

I did the same thing with a Stebel Nautilus on mine. Vast improvement over the stock one

I disconnected the original horn (the connectors just happen to be the ones needed on the relay so you can connect it straight on there). When you have the loud one, the little one doesn't serve much of a purpose.

 

[TownsendsFJR1300]

+1 on the above.

The horns may be drawing slightly more power with age, the contact switch (in the horn button) getting burnt from too much voltage going thru it.

I used the stock horn wires as the trigger switch for my Stebal air horn (which the install kit comes with a 30 amp fuse and heavy appropriate wire). Ran the included relay direct to the battery. I removed the stock horn as it wasn't needed with the Stebal.

You should find your horns louder once set up correctly. I don't know what your aftermarket horns draw, but between the stock horn, the tail lights and then ADDITIONAL aftermarket horns, a 10 amp fuse won't handle it...

You'll probably end up cleaning the contacts in the horn button as well...

 

[tedrogers]

Forgive me, but I'm a complete novice when it comes to bike electrics.

Does it require feeding back to the battery once connected to where the stock horn goes, or is it a simple plug'n'play affair? I can't really tell very easily from the link you supplied,

Thanks.

 

[Motogiro]

Forgive me, but I'm a complete novice when it comes to bike electrics.

Does it require feeding back to the battery once connected to where the stock horn goes, or is it a simple plug'n'play affair? I can't really tell very easily from the link you supplied,

Thanks.

Yes, it requires a relay and separate fused source. See the link that huxy posted for you. It even has a schematic and of course mounting location of component will vary. Get a buddy in your area to give you a hand with this if you're not familiar.
Edit: You can probably just change the fuse to a 20 ampere being it is an additional short duty cycle using the Hootaz. The main thing is you don't have a dead short and it's a momentary additional current usage but best to put it on it's own protected circuit.

 

[tedrogers]

I traced the problem to a faulty connection on the wiring loom I made.

So I have them working again for the time being on a new 10A fuse and all seems well.

I'm going to look into this relay idea for certain though, when I find one. I am having a lot of trouble getting the exact relay I need and went to 4 shops today with no luck.

The search continues...

Thanks.