Power Door Locks
The central security module controls the power door lock and keyless entry system. The lock and unlock operation is carried out by supplying ground to the central security module from the door lock control switch. The normal path of the actuators is to ground through the central security module. The door lock control switch will lock and unlock all doors by grounding the appropriate circuit to the central security module. The central security module then supplies power to the appropriate common actuator circuit to lock or unlock all doors.
Here's the diagram, I'd look at the door jamb wiring first to make sure you don't have broken wires. From what I can see, if you remove the lock switches, and ground the PK/LG wires to ground, the doors should unlock. (Grounding the PK/YE wire should lock them.) If they don't you have a wiring or Security module issue.