All of the lights in the gauges are wired to the same 12V light source and ground. There is no additional wiring for a boost gauge as its mechanical unless you got some honkey electrical gauge, in which case you're on your own. You should have gotten electrical schematics with your gauges so follow those and you'll be fine. I guess you should have gotten Isspros, Diesel Manor has GREAT directions on how to install them in your truck. You can get a multimeter at Walmart, but they're pretty crappy. I much more prefer my Fluke over those, but then again it wasn't exactly cheap.