This problem sounds alot like a bad switch input to one of the modules ! DDM - driver door module , BCM - body control module . Do you know anything about automotive electronics ?
Power Door Lock Operation
The vehicle is equipped with power door locks. Each lock actuator is powered and controlled by the door module mounted in the individual door. The driver door module (DDM) is the master control for the door lock system but the rear integration module (RIM) determines when the lock functions are permitted.
The passenger front door interior lock switch is wired to the passenger front door module (PDM). The driver door interior lock switch is wired to the driver door switch assembly (DDSA). Interior lock switches are not provided for the rear doors. The DDSA and the PDM send the lock switch requests to the driver door module (DDM) over the power door serial data circuit. The DDM then sends the lock requests to the RIM over the Class 2 serial data circuits.
The door lock operation modes are controlled by the RIM. The RIM examines the requested function from the DDM, or the remote function actuator (RFA), as well as the transmission shift selector position and the ignition switch position information available over the Class 2 serial data circuits. If the RIM determines that a lock or unlock function is permitted, it sends a class 2 message back to the DDM commanding the DDM to perform that function. The DDM then sends commands to the rest of the door modules via the power door serial data circuit to implement the selected locking function.
The automatic door lock system provides for locking or unlocking all or one of the doors when shifting the transmission in and out of PARK, or, when turning the ignition key to the OFF position. This system is commanded according to the information stored in the RIM. The RIM receives the features selected by the driver from the driver information center (DIC). The RIM commands the driver door module (DDM) which in turn commands the individual passenger door modules. For customized selections available and programming instructions, refer to: Personalization Description and Operation in Personalization.
Looking at scan data for input sensors ,switches on a scan tool should be the first step in diagnosing this problem or using a lab scope . Your best bet ,take it to a qualified repair shop .
Do you know what DTC'S are ? diagnostic trouble codes !
DTC B3377, B3382, B3387, B3392, B3397, B3452, B3457, B3462, B3467, B3472, B3477, B3482, B3517, or B3522
The switch that failed and generated this diagnostic trouble code (DTC) is part of the driver door switch assembly (DDSA). The DDSA contains a microprocessor which takes the signal generated by this switch and assigns a digital message to it. The DDSA then sends this message over a power door serial data circuit to the driver door module (DDM).
It's probably something on the lines as in these videos , but without the proper testing equipment you could spend alot of money replacing parts and still not fix the problem , your best bet ,find a guy like the guy in the video !
Door Locks Go Crazy 1
Door Locks Go Crazy 2
Door Locks Go Crazy 3