not sure about conditions needed for LEDs, but this is the correct wiring there .... what you're missing is completing the wiring before a part of it will work

"the pedal is depressed and goes through that loop...back to the front."
... where it hooks into the signals - the brake lights won't work until the turn signal assembly is all hooked up as the signals use [activate or interrupt] the brake light element

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics