What is needed to hook up the factory tachometer?
There are two wires from the tach. Red and Black.
They do not work when connected to the Coil negative and 12V. OR coil negative and ground. Just shorts out. All combinations tested.

Is there a module or something that I am missing?
Or is the tach itself bad.
NOTE: The tach wires measure almost shorted 0.020 OHMs.

 

Should hook right up..

Red wire goes to the coils neg/distributor power in, and black goes to 'chassis/engine' ground