The introduction of factory sealed beam headlights came to the automotive industry in 1940. It was then necessary to create park light assemblies. (They could no longer be incorporated in the bulb and reflector style headlight as before).
To some, the first 1940 GM assemblies were simply “add-ons”, maybe a quick design due to the fast industry acceptance of the new sealed beam system. They sat on the front fender away from the headlights and were the same on Chevrolet and GMC trucks as well as Chevrolet cars. Right and left are identical.
By 1941 GM engineers had developed park light assemblies to flow more with the body lines. Most every GM vehicle had a newly designed unit. The exception was the Chevrolet and GMC trucks. Whether to save money or there was not time, GM’s 1941 commercial vehicles were given the same park light assembly as used on the Pontiac car the year before. These 1940 Pontiac assemblies secured very nicely to the top of the long truck headlight bucket in 1941 and provided the more modern look.
By 1942 GM trucks were finally given their own park light assemblies. They were similar to the 1940 Pontiac design but were more basic. What had required four die cast pieces with the early Pontiac style now could be accomplished with one stamped sheet metal cover. This of course, required a subtle change in their glass lenses. This 1942 design was continued through 1946.