2002 Chevy Trailblazer left & right rear brake lights not working.

Yes. Bulbs are Sylvania 3157. Both bulbs are good. No voltage to rear under seat fuse block. There are 4 fuses that I can identify. #12 under the hood (stoplamp), #16 under rear seat (high mount center light), #34 (VEH STOP), and #51 (Brakes). #51 was blown, replaced, no change. #34 VEH STOP controls the left and right rear brake lights. No voltage detected to the fuse when brake pedal applied. The fact that the rear high mount is working tells me that the brake switch is operational. The problem lies somewhere between the brake switch and the rear under seat fuse block. Any ideas???

Nope......just exactly what you are doing, correctly eliminating parts of the circuit as you go. Sounds like you're getting close , don't ya just love electrical diag? Sorry about the bulb thing , but not knowing your skill level ,I just had to ask! Been many times I've seen good techs go right past the obvious --we all do at times, hope you find the cause soon. Good luck.

ziptie12, thank you for your prompt and honest response! I downloaded an electrical schematic for this vehicle. They are somewhat hard to read, however, it appears to me that the electrical signal is sent from the brake switch, mounted on the pedal, through the multi-function switch, (turn signal, cruise control, wiper assembly), to the rear under seat fuse block and eventually to the brake lights. The multi-function switch acts as an interrupter to allow the rear brake lights to blink instead of remaining constant on. This is the only thing I can think of due to process of elimination. I was hoping to find someone with a definitive answer before tearing my steering column apart! LOL

I think you'll get it , you did the right thing by getting the circuit info!! Good luck.