you're probably discharging the battery if the meter is good and not hooked up backwards - when you first start the truck you should see the ammeter dip toward discharge, and as the engine starts it should move back to neutral, faster or slower depending on how long you cranked, so how much you ran down the battery - when you first turn something on like headlights you should see a flick toward discharge, then immediate return to 'neutral' .... the ammeter shows how much juice is being sent to the battery or being taken from it, not how much the accessories are using at the moment, the electrical items should be getting supplied by the generator
it may be that your generator or alternator isn't putting out much or anything or the regulator is stuck - new charging device? if it's stock, did you polarize the regulator/generator when you installed them? the way to investigate with a meter is to check battery voltage under all the different conditions, everything off, running, and then with some electrical things on
Bill
