Circuit/System Description

The body control module (BCM) monitors the key in ignition switch. When the key is in the ignition, the key in ignition switch is closed with the signal circuit low. When the key is not in the ignition, the key in ignition switch is open with the signal circuit high. The key in ignition signal circuit is grounded when you fully insert the ignition key into the ignition switch. This in turn pulls the BCM key-in-ignition input low.