So I had the radio cut off a few times 2 months ago. Read up and installed a ground wire from battery - to chassis. Problem solved. Until.. Yesterday I got to do a 100 mile trip. Radio, Instrument panel, display, AC cutting off started on the last 10 miles. They come back on, stay on for a 2-3minutes(sometimes) and then go out again. Car drives normally otherwise. Drove 5 miles today and re-tightened any ground cable I saw. Still same thing. And airbag warning turned on. What could be causing the issue? I want to run a 4 AWG from alternator to battery + to try to solve it. OBD II sees voltage dropping from 14.4 to 12.8V, but this is only OBD module voltage. Still tells me alternator cable is loose or worse.... Any input appreciated.