I'll offer a second vote for broken wires in/near the driver's side tailgate hinge.

I fixed mine by cutting open the sheath, finding the broken wires and soldering in repair segments, followed by shrink wrapping the joints and taping up the sheath. The harnesses are quite expensive for a bunch of wires (aftermarket harnesses for my old 240 were about 10x cheaper!), and I always seem to break clips whenever I have to remove the tailgate panel. It isn't a hard job-- I can do a repair in about an hour.

My rear wiper was seized up at the shaft. I got it moving again using penetrating oil. I turn it on briefly periodically now, which seems to keep it from seizing up again.

Good luck!