Just fixed this problem on my F150. The mechanism was cruddy, with old grease, mud and whatever.
If the mech.looks unmoved (look as closely as you can) at the paint near the edges of the latch. If you see clean, shiny paint there, something's been moved. If all the paint around it looks the same, chances are good that it's still where it was before the incident. If so, try these simple things.
1) stuff the area around thee latch with nice ABSORBANT rags.
2) spray it with brake parts cleaner.*******WATCH YOUR PAINT!********
3) clean with some sort of brush if possible.
4) remove residual dirt AND brake cleaner with simple green, wind ex etc.
5) wipe dry or blow dry with air (best for nooks and crannys).
6) spray with lithium grease, NOT WD-40 (won't last).