Have read everything I can on how the ammeter is suppose to work, but can't figure out the basic operation so I can troubleshoot mine. I have the ammeter connected as per Aeroelectric Z11 diagram as a loadmeter. When I turn on the master switch, without the positive lead from the shunt connected, the meter needle goes to zero. (Amp is -40-0-+40) As soon as I connect the positive lead to the ammeter terminal, the needle pegs at +40. This is without the engine started. I tried a different wire from the shunt to the meter, same thing. I would think there is short somewhere but can figure out what to test. Help!