I'm betting it's in the wiring in this case.

But it might be in the switch. The brake light looses power when the switch is turned that way. That part is working. However, the switch should also close the circuit from the flasher to the rear brake light bulb. That part may not be happening. My '56 is "funny" about that except it's the right brake light won't work with the switch in neutral. I've found that cycling the switch several times clears the problem.



"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.