It is located at the lower passenger side beside the lock solenoid. On the 91-93s it also lights the rear seat reading lights.
Just because it latches, does not mean that it is aligned correctly. It only has to be off a little to not work correctly. You have to remove the inspection panel on the passenger side of the tailgate. It has a small lever on it.Mine latches perfectly both ways; that's not my issue.
Well, off to read the FSM!