Yes, could be a ground issue.
Battery ground cable often has 2 leads, a large one for the engine(starter motor) and a smaller one going to the Radiator Support, that's the head light ground.
Should also be a ground wire/strap from engine to firewall and/or frame.
There are 4 things that need good clean grounds
These 4 things are separated by rubber mounts so need to be grounded together with cables.
If you have a Voltmeter measure battery voltage, then with key on, engine off, pull some fuses out(one at a time) and measure voltage from the fuse connection to ground, bolt or bare metal on body, if voltage is less than battery voltage then run a wire from negative on battery to your meter, if voltage goes up then you have a ground issue, if voltage stays low then you have a 12v issue, full 12v power is not getting from battery to power distribution areas.