I have the exact same problem in my 96 grand caravan. I found that if
you hold the hatch handle out just slightly whiile trying to turn the
key it will work, i just move the handle in and out a little bit while
trying the key, it works 80% of the time. Another way I get it to work
is by hitting the power locks button to "unlock" (just unlock....NOT
lock then unlock then lock) multiple times in a row (5 or 6) this
seems to work most of the time.