Month: March 2015

I got an interesting call for help this last week that turned out to be very educational and a little humbling. A friend of mine called with what sounded like a simple electrical problem on a 1951 (yes, older than I am) Chevrolet Pickup truck. He said that he had installed a retro-fit turn signal system on it, complete with a nice chromed turn signal switch that mounts to the steering column with a stainless steel hose clamp, and replacement sockets for the lights on all four corners of the car to accommodate the new 1157 double filament bulbs .

So far it sounded simple and straight forward. Further, he said the system utilizes a typical “old school” 3 terminal flasher, which was wired in series with the battery and the “new” turn signal switch. He described the problem in a few simple words; “If you run the turn signals with the engine off, they work perfectly. But, as soon as you start the engine, they stop blinking, and stay on continuously.”

Well, I have diagnosed and fixed electrical problems in Cadillacs and Corvettes with a dozen computers in them, and built wiring harnesses from scratch for burn jobs, so I really figured, “How hard could it be to fix a simple 3 wire flasher circuit on a ’51 Chevy?”   That’s when the fight started. Continue reading “Schooled by a Flasher”