I have replaced all 4 door lock actuators, the front 2 twice, and now the driver lock is acting up again. Is there a way to lubricate these in place?

 

Have you checked the wire harness in the drivers side door jamb? I have had 2008 and a 2014 Silverado with broken wires in the rubber boot, causing the same problem as you are having. I repaird the wires and problem solved.