Ok have been chasing this problem for 3 days am at wits end. I have an 07 fxd and am having an intermittent signal and brake light not working problem. I have checked ignition switch have changed tsm and have narrowed down to a wire grounding out some where in tsm area if I turn on signals and start pushing wires that connect to tsm signals stop working, have pulled individual wires and nothing changes the lights keep blinking only when I move them together they go out!!! I really can't afford to have dealer look at it. I have also checked under fender no problems I am getting power to both switch feeds. The brake light will intermittently not work as well not sure if related. Sorry for rant.

 

Is your TSM near the fuse box. I had a loose pin on the back side of the fuse box do the same thing to me. If I stuck my finger behind the fuse box and wiggle it it would fix it temporarily.

 

Run a wire from the earth side of the brake light to a good earth on the frame, if that cures the issue then you will be sure it is an earth issue, which it does indeed sound like.

 

Two of the wires have rubbed through their insulation somewhere along the harness. By moving them together they touch and short out. Taking a single wire and moving it, you are removing a wire away from the bundle, and the adjacent wire(s) it shorting out against when in a bundle.

Or there is a wire that has break inside the insulation. These are hard to find, all you might see is a narrowing along the insulation, but if bent the break inside pulls apart and fails. I don't see that to be the issue here, but something to look out for. It often appears as a change in the color of the insulation, often a lighter colored section due to the wear of rubbing or tugging and stretching while the bike vibrates.

I'm not familiar with your bike or the TSM on you ride but moving the entire bundle would cause shifting tension at the connection point, or perhaps if a circuit board is involved broken / bad solder contacts or a cracked board with only a slight fracture that is making and breaking contact as you move the bundle.

I'll be following along to see what others say and hopefully hear back on what fixed this issue for you.

 

Ok went back out to the garage checked a few things I'm leaning towards a pin to tsm problem it got more sensitive to going out as I got closer to the connector but now can't get lights to work at all ill be getting back to it in a few days if I can not find it I guess the dealer will be next step 😡

 

Well finally got back to working on it everything points to bad tsm. I got a take off from a dealer so I reassembled the bitch now going to take it for a test ride in a few. I'll be sure to let y'all know if this fixed it.

 

Check your mods.