Hatch Lock

Try this:

Shopping list: Spray can of "White Lithium grease" and a spray can of WD-40 or similar penetrating lubricant, and spray the door latch assy, inside out, with WD-40 first. Even if you have to put window down & aim spray nozzle from top at area of latch, and soak it. Stick the nozzle inside the key slot also, and give it a few squirts. After you let it sit for a minute or 2 start working the lock on door, lock ,unlock, lock, unlock, until you feel it getting easier, now do same with key, until it starts to loosen up. Once you get it working freely, give it a few minutes, and do same with "white lithium grease". That will hopefully protect it from seizing (rusting) up again. Every once in a while when you think of it, give latch another shot of lithium grease. I usually try to do mine before & after winter, or whenever I start to feel it getting a little stiff again. Worst thing is the glass you have to clean if you aim spray too much toward glass, but small price to pay for not having to pull door panel off. If your door panel is easy to get off to allow for better access to back of latch assy, that would definately be better, but that's up to you & your experience with tools. Then you can be sure you got all the related linkages lubed where they need to be.

Thanks