Headlight Beam Level Control ECU Communication Circuit: Description
WARNING: This page is about a different car, the 2006 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
The headlight beam level control ECU receives HEAD signal from the front controller and receives engine condition (ON or OFF) from the generator. It also receives vehicle speed signal from the skid control ECU, thus controlling the headlight beam level control motor.