Turn Signal Light Circuit: Description
WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
After receiving the signal of the turn signal switch from the driver side junction block ECU, the driver side junction block ECU makes the turn signal light illuminate.
The driver side junction block ECU activates the flasher relay while the theft deterrent system gives the warning and illuminates the turn signal light and hazard warning light.