Power-door-locks open... Will then not lock

[Crist Clapper]

I can hear the plungers click/move on each door open... But no action on trying to close. Help?

[4.3LXJ]

When these Jeeps get old, the grease, which is a blend of lubricants, looses the more volatile oils and becomes very stiff. A little light penetrating oil will soak in and loosen the mechanism up