96, 97 & 03 Cravan Rear Wiper not touching glass

Hi,

Can anyone help??? I have two Voyagers (96 & 97) and a 2003 Grand
Caravan and they all have the same issue with the rear wiper not
wiping the entire area they should. They usually only wipe the left
side a little if any. I sure thought the 03 shouldn't have any
problems when I bought it but sure enough, even only being 4 years old
it still won't wipe right! Any ideas? I am thinking since all three
of mine have this issue there have to be many more people out there
with the same thing going on. Thanks in advance for any and all help
you can offer!

Greg