Bonneville America Forums Forums Technical Forums General Tech Driving Lights on Speedo Illumination Fuse ?

So - I thought the driving lights, standard triumph harness, had their own separate fuse, but I keep blowing the 5 amp speedo-illumination fuse. This last time I replaced the fuse, started the bike, everything fine - turned on the driving lights and the speedo lights immediately went out.

I am not sure, but the tail lights may be going out off of this too. I have the lights on the saddlebags working as tail & brake lights - they and the main light work as brake lights, but both are off as tail lights. Of course I discovered this assessing the damage after being rear-ended (brakes were on), so it may be related to that.

Any ideas ?

Additional info - the tail light issue is related. Replacing the 5 amp fuse brought the tail lights AND the speedometer illumination lights back.

Didn't try the driving lights since that's what blew that fuse last time.

Nothing has changed recently; I've had the driving lights and the saddlebag tail lights on since summar 2009, and I ride with them on almost all the time. Only recent change was 6 weeks it was at the dealer mid-Oct to later November when they ultimately ended up replacing the CDI and ignition sensor. I don't think I was having this problem until the end of Dec, but I only put 150 or so miles on in Dec, so I suppose I could have just missed the lights being out.

The driving lights have really thin-gauge wires; I suggest checking each entryway of the wiring in/out & about metal passages. Those are places where the insulation could become cut or chafed & cause shorting.

I had a similar problem with my driving lights. They didn't have a good ground.

Might be a silly suggestion, but add up the wattage of all the bulbs that go out when the fuse blows, then divide the total by 12. If you get more than 5 you've got a simple overload

But the driving lights are supposed to be on the 10 amp fuse 1, not the 5 amp fuse.

The driving light wires are in a sleeve (don't claim to know the terms) going into the housing, from a quick visual everything seems ok.

Going to be below my threshhold for riding for a while; it will sit til I have a chance to start taking things a part and seeing if I can see something obvious.

Maybe your rear end shunt damaged the loom or fusebox and your getting a cross feed.

Try taking the bulbs out of your driving lights then switch them on. If the fuse still blows, then you've got a short rather than an overload

Or, take the bulbs out of the brake and tail lights, then switch your driving lights on and see what happens

But check the grounds first (as FJ suggested), then do the removed tail lights one, then the removed driving lights (but with the tail lights back in). Might save you a fuse

Let us know what you find

BTW, if Gregger suggests anything, do THAT first

Thanks for the pressure Bryn. Hope I get this right.

Mark, which 5 amp fuse is blowing, the one in slot 8 or slot 10 (it can make a difference)? I've looked at both sets of drawings for our bikes and they have some subtle differences. In one print, the 5 amp fuse in slot 8 feeds the light switch, then comes out feeding the clock(light???), speedo light and the accessory light connector, then it comes back to the fuse holder where it feeds the second 5 amp fuse in slot 10. This fuse feeds the small park light in the headlight bucket as well as the rear light. If fuse 10 is blowing, then it is probably related to the rear lights or headlight park light. If fuse 8 is blowing, then it could be anything. The only problem with this logic is the fact that the fuses are in series. Fuse 8 could blow for an issue after fuse 10????? However if fuse 8 is blowing, everything quits, the rear light, front park light, clock and speedo light would quit. If fuse 10 blows, only the rear light and park light would fail. Hope that helps.

I have to admit that Triumph does not make the simplest circuits in the industry. It's too bad they don't use standard ladder logic when they make their drawings also.

Here is a suggestion. Since the fuse pops when you turn the front driving lights on, unplug the front driving lights and see if this corrects the problem. Believe it or not, it appears there are several fuses in the circuit to the driving light connector in the print (at least one 10 amp and a 5 amp). If you could get your hands on a couple of 5 amp bayonet circuit breakers and plug them in instead of the fuses, it would make things a lot easier to diagnose.

Another question. How long have you been running the extra running lights in the rear? Just wondering if you are drawing more than 5 amps with them??? If it wasn't a problem before it shouldn't be now though.

Its fuse 8 that pops. As far as unplugging the front driving lights - even having them switched off seems to keep it from popping, bu it has been a short time only.

I've had the extra running lights on the rear for about a year and a half. Two 15 LED arrays, sorry, no specs on the LEDs, checked the company's website but couldn't find any thing.

Thanks for the explanation.

If the fuse only blows when the front driving lights are on, check the wiring closely, as already suggested, for chaffing. The front driving lights are fed by fuse 1 (10 amp) and fuse 8 (5 amp). The 10 amp feed is on a purple wire to the first connection on the accessory light connector. The 5 amp feed is on an orange wire to the 5th connection on the light connector. The 5 amp feed activates the coil for the relay to keep the accessory lights on for low and high beam. Here is a link to a picture of the wiring and connector.

Again try unplugging the circuits one at a time - the accessory lights, then the speedometer light, then the clock if you have it, then rear lights and park light in the headlight bucket, to see if the fuse blows isolating the bad circuit. If you don't see a chaffed/grounded wire, don't forget to look at the filament inside the bulbs to see if one has shorted out.

If you can get your hands on these , it will save fuses.

That's pretty much what I plan on doing; unfortunately think its going to be the weekend before I have the time.