Charging Issues

Today, I hooked my battery up and found that the car is charging very weakly or not at all. The alternator shows to be charging. I reached behind the dash and wiggled the wiring to the ammeter, which is aftermarket. I was able to wiggle it and then the car had no power at all. I wiggled it some more and got the car started so it is obvious I have some connection issues there.

While playing with the ammeter, I found it to be very warm to the touch on the face of the gauge. This leads me to believe that there is some resistance there and possibly the reason for the charge from the alternator is not making it back to the battery. Should the ammeter be warm to the touch?