I think (meaning not sure), that all the lights in the Speedo and Tach are LED's. Might be a touch different than just putting in a dimmer switch. With the lights below the gauges (bright, neutral, oil press), I think those are some kind of incadesant, so a dimmer switch of sorts may work. I would suggest getting in touch with the guy that changes the colors of the lighting in the speedo/tach, he may be able to that or steer you in the right direction. There are several threads on his work, but I can't remeber his website, but I'm sure somebody will help with that!