I was squeezing my hand in behind the dash; I accidently knocked out one of the lights to a gauge. I noticed the bulb had a red rubber cover. Hence the red color background color of my gauges. With my car being blue I thought it would be nice if the color if the back light of the gauges were blue also. Apparently you can order different colors of “diffusers” at a very reasonable price. I only changed out one side of the tack and speed odometer for a nice effect.
