Hope you guys can help me out. I feel like an idiot not being able to do something as simple as checking a fuse.

I think I've blown the main trailer fuse (No. 2-5 in the primary under-hood fuse box - page 556 in my owners manual). Problem is that it is in some sort of fuse block. The owners manual says a screw needs to be removed to take it out and check it. So far so good, but even with the screw removed the block seems to be solidly in place. I'm afraid to reef on it as I don't want to break it and it seems as if there us something else holding it in place.

Anyone else run into this? Any help would be greatly appreciated.