I'm working on my 1950 GMC FC152 with the original 6V positive ground system. I had just about everything working perfectly in the electrical system, and the truck is a solid, reliable runner. Then last night I go to test the new instrument panel bulbs I had installed with the engine running, and it shut off immediately. Tried the same thing again with the same result. Talked to a guy at Fillingstation, and he suggested it is something wrong with the light switch. Any thoughts? I'm at a loss.
