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So recently I've been having the issue where I turn my handlebars to the right and the speedometer powers on and off. Engine light eventually came on and found it is the P1690 code. Researching this site I found this is quite common with certain year bikes due to a lousy wiring loom (my Thruxton is a 2013). So of course I remove the tank and checked the 5 notorious connections that have a tendency to break. Strange enough, they all look fine! So I keep going towards the back of the bike and I find some purple wires that are no longer connected (after removing the factory blue tape to check). Can someone tell me what these wires are for? Accessories? Tachometer? I have not had time to reattach the wires and check everything out due to work and rain.
 

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according to my haynes manual there's a purple wire goes from fuse 3 and feeds the speedo, tach, gps socket and the accessory socket. If you pull fuse 3 and check for continuity from that wire to the fuse socket you can confirm this.
 

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Thank you very much! Still haven't had a chance to get back on this. Hopefully this is what is keeping the bike from starting. I did initially check all of the fuses and they were good.
 

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Thank you very much! Still haven't had a chance to get back on this. Hopefully this is what is keeping the bike from starting. I did initially check all of the fuses and they were good.
Probably late to the party as usual, but I think you have found the cause of the problem. The instrument cluster has two power supplies, the Green/Red which is the normal switched supply via the ignition switch, and the Purple which is the unswitched (permanent live) supply. I don't have a schematic of the guts to the speedo but I would imagine that the unswitched supply is for functions using volatile memory (does the speedo LCD panel have a clock for example?) Anyway, if any parts of the speedo get powered down the CANbus handshake won't happen and the bike won't run.
Looking at your photos it is clear that the Purple wire has broken away from the crimp joint, possibly due to metal fatigue from the wire constantly flexing with the steering. To prevent this happening again, insert a splint of some kind which overlaps the whole joint at both ends before taping it back up, This will prevent the wires from flexing at the weakest point. Something like a plastic or wooden toothpick works well, or a length of plastic drinking straw over the wires.
 

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Probably late to the party as usual, but I think you have found the cause of the problem. The instrument cluster has two power supplies, the Green/Red which is the normal switched supply via the ignition switch, and the Purple which is the unswitched (permanent live) supply. I don't have a schematic of the guts to the speedo but I would imagine that the unswitched supply is for functions using volatile memory (does the speedo LCD panel have a clock for example?) Anyway, if any parts of the speedo get powered down the CANbus handshake won't happen and the bike won't run.
Looking at your photos it is clear that the Purple wire has broken away from the crimp joint, possibly due to metal fatigue from the wire constantly flexing with the steering. To prevent this happening again, insert a splint of some kind which overlaps the whole joint at both ends before taping it back up, This will prevent the wires from flexing at the weakest point. Something like a plastic or wooden toothpick works well, or a length of plastic drinking straw over the wires.
Yes you were correct! Finally had time to mess with my bike. Both gauge clusters now have power and the bike fired up no problem after reconnecting these wires! Now I need to just re-tape the loom and get everything back in the light housing and I will be good to go. Thanks for the help fellas! I guess that after a few runs the engine light will clear.
 
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