I have a Power Doorlock switch just inside the rear barn door of my Suburban. The problem is if I press "lock " and close the door the barn door does not lock - nothing happens... However if I press "unlock" and close the barn door - Hey presto the locking mechanism activates to unlock the barn door... Hello-oo! the door is already unlocked!

A module somewhere is supposed to operate the locks again after the barn door is closed but this is not happening on locking but for some strange reason it is for unlocking.

Question:-

How can I get the door to lock when I press the button to lock it? Any ideas?? Is there some module that is wired incorrectly? What module Where?