Circuit Inspection
WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
The door lock control switch circuit can be checked by using DTC check. See DTC B1215/15: DOOR SYSTEM COMMUNICATION BUS MALFUNCTION (GND SHORT) under DIAGNOSTIC TESTS under MULTIPLEX COMMUNICATION SYSTEM article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT. See Fig 1.