Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 999 / 749 > Blowing fuses - here we go again!

[HW]

Hiya, anyone have any idea why a 749 (2003) might be blowing the 20A fuse by the headlight that controls the starter?

Symptoms are this: parked up after ride back from Cadwell, didn't touch it until this evening. Starter dead. Fuel system pressurises, all light on ok, looks like the Run switch is off (but it's not). Found the 20A fuse blown.

"Borrowed" a fuse from my car. Started fine. Had the foresight to nick another "spare" from the car to take with me this evening. Came out the pub. Dead again - same fuse blown.

How wierd is that? Lucky I took the spare or I'd have been stranded. Anyone seen this before? I did have the rubber boot off the starter terminal this afternoon to check the terminal nut and waterproof the boot. Can't imagine how I'd have caused any grief though and the 20A should not be on that side of the circuit anyway?

[Edited on 4-5-2005 by HW]

[dave w]

Originally posted by HW
Hiya, anyone have any idea why a 747 (2003) might be blowing the 20A fuse by the headlight that controls the starter?

Symptoms are this: parked up after ride back from Cadwell, didn't touch it until this evening. Starter dead. Fuel system pressurises, all light on ok, looks like the Run switch is off (but it's not). Found the 20A fuse blown.

"Borrowed" a fuse from my car. Started fine. Had the foresight to nick another "spare" from the car to take with me this evening. Came out the pub. Dead again - same fuse blown.

How wierd is that? Lucky I took the spare or I'd have been stranded. Anyone seen this before? I did have the rubber boot off the starter terminal this afternoon to check the terminal nut and waterproof the boot. Can't imagine how I'd have caused any grief though and the 20A should not be on that side of the circuit anyway?

Sounds like you have got a short in your wiring/ connectors.... thats going OC (open circuit) when the voltage drops... But i could be wrong

[antonye]

Fuses blow because something is drawing too much current - and that's usually because a connection is touching earth when it shouldn't be, or some component is breaking down and has shorted to earth.

Because it's only happening when it has been left, it sounds to me like it's the alarm/immobiliser circuit which is arming once the bike has been switched off, and it's then shorting and killing the fuse.

Either that or because you're putting the bike onto the steering lock, it's pulling on a lead or rubbing against something which is causing the short.

Talking to Mitch at TecMoto the other weekend, he was moaning that the wiring on the 999 series is really, really tight. We laughed that it was the Italians obviously trying to save money by shortening their cables, but there may well be some truth in it!

As DCR says, check the wiring in the cockpit as something might be catching and shorting. If that all looks ok, leave the fairing off so you can see the fuse, park it up and watch what happens. If the alarm/immobiliser comes on and the fuse pops - there's your problem.

[antonye]

PS. Use the wiring diagram (I think there's one in the manual) and see what is inline with that fuse, as this should help narrow it down a bit.

[HW]

Thanks for the comments. I will be going out to take a look in a bit. I was wondering whether it was the act of starting it that blew the fuse ("managed start" worked fine last night, I could hear the starter going for a few seconds) or whether it was something else.

[antonye]

According to the manual, the 20A fuse next to the headlight is for:
"1B = Stop light – horn – flasher - starter contactor = 20 A"

So you might want to check these particular things first.

[HW]

Oh right .... brilliant thanks for looking that up. I fitted an LED tailight unit a while ago, so that might have shorted out. Didn't use the horn or flasher last night.

[antonye]

Does yours have an alarm? Does it flash the indicators or toot the horn at all? It might be one of these that are faulty, and maybe the alarm tries to indicate that it is arming (by horn/flashers) and pop goes the fuse.

If it's an LED tail light, LEDs need to be wired the right way round and it might be this that is causing the problem. Normal bulbs don't matter.

If it was me, I would:

1. Get a load of spare fuses
2. Start the bike and watch for when it pops - try the brake light and indicators.
3. If it starts and it's still ok, switch it off and watch for it to pop - might be the alarm.
4. If it's still ok, try putting it on the steering lock or wiggling the bars around as it could be a loose wire/connector.

Hope this helps,

[jobr]

Originally posted by HW
Hiya, anyone have any idea why a 747 (2003) might be blowing the 20A fuse by the headlight that controls the starter?

A Boeing 747 you must have a huge hanger to keep one of those in????????????????????

[HW]

Originally posted by jobr

A Boeing 747 you must have a huge hanger to keep one of those in????????????????????

DOH! Have you not heard of that particular varient then? Only for us northern types who have the strength to handle that kind of power!