I have a 2015 3500 with a tailgate camera. Manual is no help. I have traced the wire to a plug connection but even after moving a small red latch on the connector, I cannot remove the plug to allow me to remove the tailgate. Anyone with a 2015 that has figured this one out?

 

the red latch is a lock. once the latch is slide to unlock, you probably will find a tab that needs to be pressed, then pull the connector apart

 

Tech2 hit it on the head, it's just a lock clip. Look over the connector to find the tab, you might need a small flat head screw driver to help push the tab down (DO NOT PRY), but there will be a push tab on there.