I purchased a used underdash wiring harness that did not have the connections for my tach. I'm trying to run just tach wires to get it working. I grounded the black wire from my tach and tried hooking up the red wire to the positive side of the coil but it shorts out my coil. I tried the negative side and same thing happens, shorts out my coil and the engine dies. I know I'm forgetting something fron shop class 101. Anyone know of an easy hook up for a tach?
Jim
Jim