Wagoneer Tailgate Window Problems

Recently bought a 1977 Wagoneer. The tailgate window was down when I picked it up. The switch does not seem to work. I pulled the inside panel off to try and do it manually but the glass seems to be stuck. You cannot access the window motor with the glass down. Any suggestions on what could be causing the glass to be stuck?

The assembly is probably frozen up, you can disconnect the arms from each side of the glass, though it's not a fun thing to do.

It used to be common for the wire harness to break at the hinge on the gate, might be a place to look.