[jimfulco]

The lock button should move up & down with the key. The locks can be quite stiff on old trucks, especially if they don't get used much. A good hose-down inside the door with WD-40, repeated daily for a few days, can be a help. Move the button up & down by hand while everything's wet. Shoot some inside the lock cylinder with the red tube, also, then work the key around in it some. Don't try to force it, just jiggle as far as it will go.

Once you get it freed up, get some brake cleaner or something and clean all the WD-40 out so it won't gum up next year, then lubricate the cylinder with graphite or a non-gumming spray like Break Free CLP.