So I'm using the pertronix d71202, the tachometer works fine but the light doesn't work. I've changed bulbs and checked fuses. Their is a tan, black and black wht stripe. The tan goes thru the firewall to the fuse box(see attached). The black/white stripe is going to the tach spade in the distributor cap. And the black is the ground. Any clue why the light won't work?