Did you use a test light on the brake switch? Make a test light if you don't have one.
STEP 1. When the switch is closed, you should have voltage on the white wire going into the turn signal switch.
1a.(white comes from brake switch) 1b.(emergency flasher switch should be in the OFF position)
STEP 2. If you have it there, then probe the DARK GREEN and BROWN wires coming out of the turn signal switch.
STEP 3. If you have it there, the wires go to the driver's kick panel plug behind the parking brake. Check the same 2 wires there. They go to the left and right brake lights from there. Check IN and OUT of that plug.
If you have step one but not step 2, unplug the turn signal connector and hook a jumper between WHITE and the BROWN wires and see if you get the right brake light on.
Let me know what you get.