Unlock Warning Switch Circuit: Description
WARNING: This page is about a different car, the 2007 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
The unlock warning switch detects if the key is in the ignition key cylinder.
The unlock warning switch turns on when the key is inserted into the ignition key cylinder and turns off when the key is removed from the cylinder.
The body ECU is connected to the unlock warning switch via terminal KSW and key detection status signals are input to the ECU.
The body ECU applies voltage to the unlock warning switch via terminal KSW. When the unlock warning switch is on (there is continuity between the switch terminals), a signal indicating that the key is in the ignition key cylinder is input to the body ECU. When the switch is off (there is no continuity between the switch terminals), a signal indicating that the key is not in the cylinder is input.