Interior Light Circuit: Description

WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

The Interior lights turn on when a door is opened, and turn off when the door is closed. This illumination setting can be canceled using the overhead J/B switch.

In addition, the interior lights blink while the theft deterrent system is sounding an alarm.

The turning on and off of the interior lights is controlled by the main body ECU LH based on various signals received through BEAN communication.

The main body ECU LH includes a MOS-FET (Metal Oxide Semiconductor - Field Effect Transistor) circuit that fades the interior lights in and out by duty control.

This MOS-FET circuit has an overheat protection function as fail-safe. If the main body ECU LH becomes excessively hot, the interior lights turn off and remain off.

Normal operation will resume when the conditions required to turn on the interior lights are met again. If the vehicle is equipped with scuff plate lights, their operation timing is the same as that of the interior lights.