Make sure you check the wires for continuity, to insure that you don't have a wire that is broken somewhere under the insulation.
Also, remember the sensor produces an AC voltage output
So I won't get a light reading on these wires? Sorry, I'm no electrician. Also I ended up putting a new mini tach on tonight, wired up as before and it still doesn't work. I'm afraid there may be connection problems here as well. I've got no speedo and no tach!