I recently bought a 96 Yukon. I love it, but it needs a little TLC. I have the rear barn doors, and the passenger side door opens fine, but the driver side door won't open at all. When I pull on the handle it will unlatch at the top, but the bottom latch stays closed. What can I do to fix this? I've tried hosing what I can reach down with WD40, but it's still stuck fast.