Circuit Description
WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.
This engine hood courtesy switch is built into the engine hood assembly and goes on when the engine hood is opened and goes off when the engine hood is closed.
The engine hood courtesy SW signal is sent to the Driver Side J/B ECU, and through the multiplex communication circuit to the Theft Deterrent ECU.