If I'm reading this right, the WT/DG wire on the door lock switch comes directly from the BCM and when the switch is activated, it connects to GND at G200. So if you can ground the WT/DG wire, the door locks should unlock. There is a resistor in the switch that changes the resistance to ground for the lock function. look at page 8w61-4 on the service manual to see the switch circuit. This should help you diagnose whether it is the BCM or a bad switch. Hope this helps.