I have an MSD box with a tach output. My shift light has 2 wires, I figured out which was ground and which was power. When I hook up the power to the tach signal and ground the ground. The light just blinks whenever the car is on... What should I do?

 

try doing a search on a search engine..i had done mine that way before and found detailed instructions on how to install it...but im sure someone here knows how...