Good to Know
This is great information to know about the later model cars.
I also had drastically different lighting between my LED lit switches and the rest of my interior lights. I ended up finding a replacement bulb for the heater control and LEDs for the instrument cluster as well. After doing that I got the bright, even light I wanted in the interior.
Obviously, these LEDs were only a part of that process (but probably the most time consuming part, hence why I am offering to make them for others).
My car specifically is an '81 and all the switches are lit by the fiber optics. Counting the switches that light up would work well for my car and other cars that have similar interiors to the '81, but perhaps the best way to know how many LEDs one needs is to count the number of fiber optic lines currently in the car. I believe I will be recommending that method from now on.