Well, on the 230SL, it's a matter of opinion whether they light up. There's a light bulb and a tiny plastic pin that protrudes through the center of the knob that's supposed to bring light out to the front of the knob to indicate where it is on the dash in the dark. After 50 years, the pin doesn't bring out much of the 2 watts out to the front, so you might say it lights but doesn't light UP!.
Tom Kizer
