All cars have some kind of fail safe. So, it should be somewhere inside, close to the bottom center of the tailgate. There's gotta be one for your truck too. If I'm not mistaken it should be in the same place like mine. Remove the cover and move the lever.
@@4x4AUTOBOT My 2010 Pathfinder doesn't have a manual release either. I pulled the panel away from the drivers side and hooked up the new switch and then opened the hatch to get at the last screw holding the panel on, then Bobs your uncle.