Those hinges gradually fail. Several ways, one of which causes the hinge pin to move sideways and sever the wiring harness.

The wiring harness itself fails, after a gazillion flexes over the years.

All power to the cargo door goes through one hinge or the other. De-mist, wiper, license lights, plus lock and 3rd brake light later models.

There is a ton of information on this board about what do do. Check the archives, and so a search. there are ways of re-habbing the harness itself, and you can buy harnesses from placed like fcpgroton.com or other BB sponsors.

You will need to assemble some tools and things. One is a pole or 2 x 4 long enough to hold the cargo door open while one hinge is removed. Another is some sealant to use when reassembling the hinge.

Good Luck,

Bob

:>)