I had the same trouble with my breaker,.... lack of use and lube. I found a search didn't really help much, found one guy had apparently pushed the right part of the lock between the mechanism and the skin, but his hands must be smaller than mine. I gave up and (as its a breaker) just cut away the rear corner and cut the latch loop away. Hope you find an easier way. Lots of lube to start with, absolutely soak it, and see if you can unstick it. If anyone has one out of the vehicle it might help to understand where you need to get a finger (or something) into the mechanism.