Put both ammeter wires on the same ammeter stud to bypass the ammeter if you want to eliminate the ammeter (if I'm reading this right) & check/clean the ring terminals first. Neg voltmeter terminal/case to ground, Positive voltmeter terminal to switched 12V either fuse box or ign switch ign1 (run) wire

live every 24 hour block of time like it's your last day on earth