Gray notes his shop works "on all makes and models of heavy-duty trucks and trailers" now, more than half a century since his father, Roger Gray, founded the garage in 1963. Gray started working in 1976 and, as with Mallinson, has persevered through the "evolution of electronics in the automotive industry. ... You have to know how the system works and how it is wired, because there are many things that can cause" a fault code other than bad underlying components. For many trucking today, Buchs said, it feels like "what we know about these systems is they work, or they don't work. And ther...