very weird.. tach only works from positive side of coil
 

ive got a 82 2x4, 22r. all stock. i put a tach in it today, positive off the sig lighter, lights off the wire to the heater control light, and grounded from a steering colum bolt... hooked up the green to the negitve side of the coil... nothing... messed around with different wires from the coil... and figured why not try the positive side of the coil...

Sure enough it works.... im very confused.. ive had the truck since feb and never had a issue with it or changed any or messed with wires...

Whats going on? i drove it around for a few miles and nothing got hot or smelled or melted.....

Im lost.... but it works good... :eeek:

lol well im glad no one said disconnect it its going to blow up... drove 100 miles today with it and no issues... :saw: