In the instructions for the separate two wire harness, (12 volt, foot start with alternator in a 49 1/2 ton) it refers to a connection running from the "B" terminal on the starter motor to the (-) terminal on the ammeter. What is the "B" terminal? Logic would say "Battery"? I'm adding gauges from Classic Instruments and I'm being told to attach the (-) terminal on the ammeter end of the wire to the ground post on the gauge and then run a ground wire to the cab. Something doesn't sound right. Is that not running a "hot" wire direct to the body of the truck?