Ok, I have. 2012 Fatboy Lo, I have Hogworkz turn signals, front and rear, I also have their 3 bar led taillight. I have replaced the front brake switch, I have replaced the rear brake switch, I have replaced the rear circuit board, with an OEM circuit board, and I get b2161 immediately! I go clear the code and it comes right back on. I have traced the wires, plugs you name it and I can’t find a single nic. I have also swapped the same rear taillight with my other bike and it works fine. I am at a complete loss right now as to why I can’t solve this. I have replaced every single part you can! HELP!!!
To add, if I clear the code the Speedo light will stay off until I push either the front or rear brake, doesn’t matter, either one will trip it. The running light on the brake works the brake light doesn’t.

 

It's throwing the code because the BCM is reading something is amiss....

Most times I've read about this code, it is because of a failing or failed brake switch. I would double check the work you have done, to ensure all switches and the circuit board have been installed properly and not damaged during the install.

If all that is good, then time to reference the factory electrical diagnostic manual and follow the flow chart checks for that code.....

One last thought, do you have a run/turn/brake module on this bike....? If so, that module could be failing. Remove it from the system and see if things go back to normal operation.

Sorry, but that's all that pops into my mind. Electrical problems are not my favorite and hard for me to follow without having hands & eyes on the bike myself...

Good luck with your diagnosis... let us know what you eventually find...

 

So after this post I pulled the battery, chased wires, looked for nics,again, and then for ***** and giggles I pulled the 2 plugs off the ECU. They were gritty/Sandy, plugged everything back in and everything works! How dumb is that? So solved and back in the road, but the fix I’m still scratching my head! Thanks!

 

It's always a good idea to check and clean electrical contacts when developing problems with a canbus bike. All those canbus modules talk to each other. If you have dirty, corroded, or loose connections, it will wreak havoc with that communication...

Good job, glad you got it fixed...