Weird brake light issue

Just picked up this bike used, 2010 WR250R. I'm having a hard time troubleshooting root cause, hoping someone here can help.

So here are the symptoms:

• Tail light lights up fine, signal lights, horn and headlights all work fine.
  
• Neither front nor rear brakes activate the brake light.

Here's the troubleshooting I've done:

1. Switched out entire tail light assembly with new OEM unit. Same issue. So that rules out the tail list assembly being broke (someone else reported an issue here so I tried this first)
   
2. Plugged in new rear brake switch, manually pulled the spring to mimic activating the brake, still no brake light. (Tail light remains on).

Given this, I'm quite confident the issue is not with the tail light assembly, or brake switch. What else could it be though??

No connection from the brake light switches to the taillight.
May be that a wire is unplugged or broken.
Time to look at the wires and test for continuity.

Have you asked the previous owner what he did to the bike?
May shed some light.

Wondering if your brake light is actually on all the time. I fit some Bark Busters on the weekend and the brake lever touched the metal frame. When this happened it activated the brake light switch so the light was on all the time.

Get a multimeter on the disconnected 3-prong plug with the ignition on. One prong to the ground prong should always have voltage and the other cycles with the brakes.