The ammeter might be toast but let see if it is. Get you a couple pieces of wire. Make a good connection to battery and connect other end to one post of ammeter. Take all other wires off ammeter. Take your test light (it looks like an ice pick with a bulb in the handle and a ground wire), hook the ground lead to other side of ammeter. Stick the ice pick part on a good ground or better yet the other post of the battery. Test bulb should lite and you will get a deflection on the ammeter needle. Don't worry about polarity, it will swing one way or the other. Let us know.
