Ultra Gauge ammeter?
 

Perhaps I'm missing something, but does the Ultra Gauge display the current draw on the alternator/battery? All I could find was an odd voltage gauge. Odd as in it had "bank 1 something voltage, bank something 2 voltage, etc." I have no idea what this means.

Those small voltages would be the O2 sensors. There should be a supply voltage for the OBDII port that the unit can see, some others have posted about that, would be above 12 volts. Like 13.6 - 14.4, etc. As for amps, nope. I used a commercial clamp on DC amp meter, and my D1 stock alternator has to deliver about 85 amps at idle with everything on, wipers, AC, heater fan, lights, radio (basic after market, not a blaster model designed to crack the windows of Jeeps at 200 meters). A D2 will draw a little more. The stock starter draws almost 300 amps when cranking the truck.

Thank you sir!

Yes you can, look for the UG VOLTS reading, that will tell you the volts to the OBD port, which should be what the truck is putting out.