Update
Engine running and meter attached to negative terminal and to engine ground . It shows 0.0 . I played around with moving it to a bare spot on that ground wire against engine still zero. Jumper cable connected to those give no difference
But
Negative post to ground on fire wall and negative to headlight ground
Engine running with heater on shows approximately 6.2 with but lights turned on 6.60 but soon dropped to 6.20-6.40 as heater blower slowed a lot. Blower and hvac turned off and just lights on shows 5.20 this is headlights and fog lights . Drops a little with fog lights off.