I received my Westach gauges from Geno's Garage and have one question. These gauges are backlit with a small incandescent lamp. On the installation instructions the directions indicate the light should be connected to any circuit which is energized when the engine is running. I would prefer to hook them up with the other dash light which only come on with the headlights and can be dimmed. Does anybody know which wire(s) under the dash are the circuits for the dash lights?