Fuse for Horn\Brake Lights

Dazza · 12-Oct-2003, 20:29

The 7.5A fuse on my bike keeps blowing when I turn the ignition on.
I only have a spare 30A fuse so i've put that in and it doesnt blow!
Any ideas??

Thanks muchly!

Dion · 13-Oct-2003, 00:25

<Any ideas??>
Yep you've got a fault that causes more than 7.5a and less than 30a to be drawn thro' the circuit

Dion · 13-Oct-2003, 00:35

Oops, sorry there was supposed to be more than that.

You do have a serious fault tho', the larger fuse will allow more current to flow than the circuit is designed for - you could start melting wires etc - not good!

I would suspect you have a high(ish) resistance short, don't have a circuit diagram to hand but personally I'd start by looking at the horn/brake light switches on the bars.
Do the horn and brake light both still work?
If one of them doesn't then obviously start by suspecting this part of the circuit.
I don't think I'd ride it with the larger fuse, I'd prefer not to have a horn and flap my arms around!!

DJ Tera · 13-Oct-2003, 12:30

Hmmm mine started doing this in the pits at brands - interesting riding with no revcounter, neutral or reserve lights!

It went away after a few hours though, it must be a Ducati thing

Jasper · 13-Oct-2003, 15:17

I'd take the 30A fuse out first!If the current the fault is drawing is 28A and the wiring only designed for 7A,you could end up with a lot of melted cables or a fire!

Dazza · 13-Oct-2003, 21:10

Thanks for the replies.
I havent run the bike with the 30A fuse, I just put it in to check the lights and horn still work, and they do...
So should I check the wiring, the switches or just leave it to the experts next time it goes in to Tecmoto?

Dion · 13-Oct-2003, 21:52

Well, it depends how confident you feel - I would get stuck in, but then I reckon I know what I'm doing, others may of course disagree!!!
It certainly can't hurt to have a good look around, electrics aren't magic - there must be a short somewhere - you just have to find it!

as Weeksy said any mods or repairs that may have been done are prime suspects.
Try to follow all the cable runs and look carefully for any wear marks or pinching.

Has the brake light cable got trapped where it goes up into the seat unit for eg.

Failing that some simple fault finding should be possible - get some more 7.5a fuses and try disconnecting the brake lights / horn and see if it still blows the fuse.
Does the fuse blow immediatly or only when you put on the brakes for eg. It is possible for bulbs to go short circuit so it may be as simple as that.
Good luck, let us know how you get on
D

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12-Oct-2003, 20:29	#1
Dazza Registered Forum User Mille Posts: 203 Join Date: Oct 2001 Location: Shoreham by Sea, West Sussex, UK Mood: Rossi-tastico! Fuse for Horn\\Brake Lights The 7.5A fuse on my bike keeps blowing when I turn the ignition on. I only have a spare 30A fuse so i've put that in and it doesnt blow! Any ideas?? Thanks muchly! Reply

13-Oct-2003, 00:25	#2
Dion Registered Forum User Posts: 38 Join Date: Jun 2001 Location: Dorset, UK <Any ideas??> Yep you've got a fault that causes more than 7.5a and less than 30a to be drawn thro' the circuit Reply

13-Oct-2003, 12:30	#4
DJ Tera Registered Forum User Big Twin Posts: 1,724 Join Date: Aug 2002 Location: London Hmmm mine started doing this in the pits at brands - interesting riding with no revcounter, neutral or reserve lights! It went away after a few hours though, it must be a Ducati thing Reply

13-Oct-2003, 15:17	#5
Jasper Registered Forum User Ducati Corse Posts: 3,707 Join Date: Jun 2002 Location: YORK I'd take the 30A fuse out first!If the current the fault is drawing is 28A and the wiring only designed for 7A,you could end up with a lot of melted cables or a fire! Reply

13-Oct-2003, 21:10	#6
Dazza Registered Forum User Mille Posts: 203 Join Date: Oct 2001 Location: Shoreham by Sea, West Sussex, UK Mood: Rossi-tastico! Thanks for the replies. I havent run the bike with the 30A fuse, I just put it in to check the lights and horn still work, and they do... So should I check the wiring, the switches or just leave it to the experts next time it goes in to Tecmoto? Reply