That's why you need to make some checks and yes
Also we need to clear up here. Do you still have the original ammeter or was it replaced by an aftermarket ammeter or did you remove it and replace it with a voltmeter?
Also, BE CAREFUL. Disconnect the battery ground. If you still have an ammeter, those are high current connections and you can burn stuff down. If you replaced the ammeter, the original big red and big black must be bolted together (and taped) which had originally connected to the ammeter