Open Door Warning Light
WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect the connector from the door courtesy switch and ground terminal 1 on the wiring harness side, and check that the warning light lights up. If the warning light does not light up, check the bulb circuit. See BULB CIRCUIT under CIRCUIT TESTS.