I would THINK you could test each LED bulb with diode tester on dvom, and hot and ground on circuit board, mark the ground side of each and install. A non polarity sensitive DIODE Bulb could be more to go wrong? IDK how this is accomplished, nor if old dashes rely on power being back fed to accomplish anything.
A few years back my bud put them in the dashes of all the semi's in his fleet.
Don't know what brand of bulbs he used. Changed back to standard incandescent, because of frequent failures.
I'll check with him if he found good bulbs yet, all his trucks are LED front to back now. Either he found something good or is swapping out a lot of lights.
If their is something good out there he will be in the know.
