So you are saying you had no voltage between the pin at one o'clock(+) and the pin at 7 o'clock(-). If so, then it is in the wiring harness some where or a bad connection on the back of the connecter. Suggest you pull the fuse, put a jumper between + and - of connector then go to fuse box with your meter and check for continuity between frame the the lug of the fuse that does not show voltage to the - of the battery. If no continuity then the charge line is broken or the - is not connected to the truck frame good at the back of the truck. I doubt that they run the - all the way back to the battery. Just my thoughts.