lights flicker at cruising rpms fine at idle?

no somehow the bulkhead connectors fell out into the car....I checked them cleaned them and the wires and everything look perfect

I tested voltage at battery with car running and am getting a consistent 13.5-13.6 volts and at highest fluctuation when i turn everything on and full draw of heater, radio, lights etc.... dropped to 13 volts and highest with everything off and car first started 14.0 volts at idle....I also performed the first two tests you mentioned and got a reading of .02 volts


I do only have the battery to engine ground no others, voltage regulator bolts are stripped but being held in pretty solid