You can pop the covers off and see if there's water in 'em either that or drill two small holes and shake 'em.
They have contacts in them and if they have water in 'em it'll make a false link. You can't hurt em by opening the cover if they're bad. Actually the covers are to keep moisture out.
Momma never told Dodge that it's be taking Scuba lessons.
I'd take a hack saw and cut the tops off. Careful not to go too deep. or three sides so it can be folded back over.