Power door lock on driver side will unlock all doors, but will not lock doors. When I press button to lock, there is no actuator sound - just the click of the button. Passenger side power door lock will open and close all doors. Removed entire driver side power lock/windows switch configuration and replaced with another one that is known to work and got same results...driver side door lock switch will only unlock. Not sure what to look at next and would like to know what I am after before I take door panels off. Would also appreciate any references to wiring schematic for door locks - preferably something online. Any suggestions for next step would be helpful.

 

Suggest checking the wiring going between the driver’s door and chassis. Often this wiring breaks down over time due to the constant door opening and closing.