I found some time to start the install for my Triumph heated grips. While the kit came with a harness, the Thruxton appeared to be pre-wired.
I really wanted to use the existing plugs, but there is just not enough slack to draw the plug back through the bars. If I managed to connect the plugs inside the bars, how difficult would removal be in the future? My guess is the factory harness is also used with other bikes. It makes no sense otherwise.
I decided to undo the factory wiring harness for the left side, to explore my options. To understand why I needed more slack, here is the relevant bit from the instructions, which uses the harness provided with the kit:
This is inside the left-hand harness:
Which juuuuuust gives enough slack:
I considered creating some extenders for the factory harness. The connectors are JST JWPF; 4-pin on the left, 2-pin on the right. But I worried about getting the extra plugs and wire to fit within the controls.
Replacing the harness sheathing was harder than I expected. The “flexible” heat-shrink tubing I tried was far too stiff. I ended up ordering harness tubing from http://www.cycleterminal.com/ which is thinner than OEM but worked well. To use the non-shrink tubing, I had to remove the plugs at the headlight end. This is how you remove pins from a JST JWPF connector:
I was really concerned about the throttle-side wires getting cut; the hole provided by Triumph is sharp and others have reported having problems. I widened and smoothed the hole with my dremel and some 500-grit sandpaper. There seems to be no binding after install.
I removed the extra left-side wiring and plug, but ignored the right-side… I didn’t feel like cutting into a second harness.