I just finished installing a custom backlight in my pro gauge. Comes on when the progauge does, no internal battery etc.

cool.
screen swap or leds inside?

WOW -- that's pretty cool!!!!!

It's 3 LEDs on a panel. the panel was actually an led backlight for another screen. I cut it down as small as I could. same screen it's just inverted, I the polarizer strip I installed is 90* from factory. the film is linear so it worked nicely