instrument cluster light switch & panel light rheostat

[dllubin]

Ok, I’ll look into that. First time I’ve heard only a portion of the bulb is used. Maybe just a brighter, higher wattage incandescent is the way to go? There is some chatter here on different rheostats reacting differently. I must have confused mine as one that would not work.

The numerical aperture of that fiber is about 0.5 which means the acceptance angle is about 30 degrees. That means that photons arriving at greater angles than that will not be transmitted down the fiber. So, most of the light is wasted in that setup.

I would go with the approach that Mike took above with LEDs for each switch and connect them to the dimmer.