Key Interlock

Battery voltage is supplied at all times through BRAKE LIGHTS/HORN FUSE 45 (20-amp) to the key interlock switch. When the key is in the ignition switch, battery voltage is supplied to the key interlock solenoid and the key interlock circuit in the Interlock Control Unit (ICU). If the A/T gear position switch is in any position, but Park, battery voltage is applied to the transistor. With the transistor on, the solenoid is energized and the key cannot be removed from the ignition. When the A/T gear position switch is in Park, the transistor is grounded at G401. With the transistor off, the solenoid is not energized and the key can be removed from the ignition.