Hi Eric., welcome...!
If you can get to the plug-on wire to the fuel sending unit on the tank., you can touch it to ground (key on) & have a helper watch the dash gage. If the needle moves.... the gage is OK., may be an issue with the sending unit.
The sending unit gives out an ohms value depending on the fuel level.
Not sure on your "dc" ... think you're refering to "voltmeter"