The ammeter goes in line in the feed cable to the battery as Cletis says. The load -the wire that connects to your fusebox, lights etc. needs to be connected to the generator/alternator side of the ammeter too. Then the ammeter will show the proper discharge when you have lights etc. turned on without the motor running and will also register the correct nett. charge when the motor is running.

You say you've removed the voltage regulator. keep in mind that if you've fitted an alternator, the needle on an AD truck ammeter is hard over at about 40 amps charge or discharge. If you start your truck with a low battery and a 63 amp or bigger alternator, the needle will peg on the charge side because for a short while the alternator will send its maximum charge to the battery. You can fit some power resistors in the ammeter circuit to fix this problem -there was a thread on here about this a few months ago.

Stuart.