Hi guys newbie here from Oz. I own a 2016 Triumph Thruxton 1200R and i have an annoying electrical problem. Every time the brakes are applied (front or rear) the 10 amp fuse number 3 blows, when this happens i lose my horn, my tail light and brake light and also the DRLs, the indicators remain working, so must be on another fuse. I replace the fuse and everything works fine until i apply one of the brake levers. Any ideas as what the problem might be? thanks in advance
I’d suspect a wire shorting out and as it’s when each brake lever is used it looks like it’ll be down the brake light end, check for insulation being worn away on the wires. Change the bulb. Some electrical guru will be along soon to tell you how to run checks on relays or whatever is used
unplug the rear light and try. Then the front light. At least it'll get you closer to an eventual problem. Check the rear brake cable too!
Have removed the loom that runs to the tail light and indicators, removed the hard plastic sheeting from it only to reveal everything ok. No insulation damage to any of the wires. Ran a continuity check on all the wires in that loom and all came up ok.
Check round the headstock. There was a recall for the thruxton (and a few other models) regarding wires round that area. I not sure but I think the thruxton recall was only valid if you have the cafe racer faring installed.
I had a split in a wire you could not see till it was bent, a tiny little 1mm cut, right next to the bracket. I used about 5 fuses trying to find it.
To save on fuses, remove the blown fuse and put a test lamp (small 2watt bulb) across the fuse terminals. The bulb will illuminate when the short happens. You can them move the wire about to see when the bulb goes out. This will show the area where the short is. Do-not use a headlamp bulb as it will pull too much current. Not to be used on circuits where ECMs are involved as they will always draw some current for internal memories. Alfie
Would also recommend that if it is fitted with a twin filament build to check if one element is shorting to the other. Just try a new build and make sure it is fitted the correct way round. Alfie
You could try disconnecting the tail tidy and apply the brakes to see if the short is in the tail tidy or before. Alfie
I have read in a previous post somewhere that a wire was trapped in a tail tidy and was causing fuses to pop. Can't find it but I certainly remember it. As @alfie says, worth a go.
That was me possibly. The short I mentioned earlier was right up against the tail tidy on the numberplate light wire.
Have spent another day in the workshop, all to no avail. Proceeded with the bulb method instead of a fuse, switch on ignition all is good, all stationary lights are on and working as normal, bulb is not lit, however depress the front brake lever, or the back brake lever, or press the horn button the bulb lights up and the tail light goes out, eventually changed the rear light assembly with a known good one, made no difference whatsoever, did exactly the same! Whilst all this was being checked the headlight was removed, as i had been previously checking the connections in the headlight shell, but when i connected the small DRL plug into the head light i noticed that the tail light dimmed considerably? Out comes the volt meter, with the DRL plug removed from the headlight i was getting 12 volts to the rear tail light, however when the DRL plug is connected back into the headlight, the voltage drops to 6 volts!
Having disconnected the Tail Tidy connector without success, you can try following the wiring towards the front of the bike and disconnect connectors as you go. Most of my experience is with cars where we had access to the wiring diagrams which would show you the location of all the connectors. With cars being a bit longer we used a process called 'the Half Split' approach where you would pick a connector half way between the source and the consumer. Work out what voltage you would expect to see. If less than you expect, move towards the source. If more than you expect, move towards the consumer. Alfie
