Hazard Warning Switch 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 hazard warning switch sends a signal to the turn signal flasher.
The turn signal flasher blinks the turn signal lights.
Also, the main body ECU RH activates the flasher relay when the alarm of the theft deterrent system goes off.