Hi guys!
so I’m installing Yaffe rear fender on my ‘14 Street Glide Special, it comes with custom lights. Original setup was running lights/turn signal/brake lights, license plate lights and tri-bar light at the bottom of the fender. With new setup I would be eliminating tri-bar light. the harness under the seat has six wires (1-ground, 2-running light, 3-accessory power, 4-left turn, 5-right turn, 6-brake). New lights have 4 wires coming out of each tail light (1-ground, 2-running, 3-turn and 4-brake) so the accessory power is missing. The issue that I’m facing: when I connect ground, running, and brake everything works great, but when I connect turn signal wires - turn signal works but it cancels break light power meaning when I press break the whole tail light goes off, I release break and lights come back up... did anyone ran in to it? What can be the issue? I tried switching running with accessory power - still the same affect, tried connecting then together -same... any suggestions greatly appreciated.

 

wire color coding would help
the bcm controls the brakes and such. sounds like a loss of ground path.
not saying this is it but for ex
brake sw applied, bcm sees power from sw, bcm sends power to brake lamp, power flows through lamp to ground.
IF when turns are called for, power goes out but power is across the brake circuit also, power equalizes so you have 12v on both sides, ground path is lost.
hard to say with out seeing.
do you have the schematic?