For Buick 1970. The topmost light bulb on my speedometer was removed and someone put a plastic plug in its place. I assumed someone had to replace the bulb holder but choose to plug it instead. Now I saw yet another gauge cluster on ebay where the same is done. I am starting to think this is not a coincidence? Is this is an undocumented stock feature? Or something people commonly do for some reason, e.g. the upper bulb creates some annoying side effect?
