Circuit Description
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.
The ECU power source supplies power to the actuator and sensors, etc. when terminal No. 16 (GND) and the cruise control ECU case are grounded. See Fig 1.