Circuit/System Description

The vehicle power mode master is the body control module (BCM). The vehicle ON/OFF switch contains two individual switches that provides redundant switch inputs to both the body control module (BCM) and the keyless entry control module. The BCM monitors this signal to determine if the switch is released or pressed. When the vehicle ON/OFF switch is not pressed, voltage on the signal circuit is pulled down through two resistors in the switch. When the vehicle ON/OFF switch is pressed, voltage on the signal circuit is pulled down through only one resistor, changing the voltage seen at the BCM and indicating that the vehicle ON/OFF switch is pressed. The power mode master will activate relays and other direct outputs of the power mode master as needed according to the calculated power mode.

The keyless entry control module monitors voltage on the switch is the same manner as the BCM, but monitors the second switch located in the vehicle ON/OFF switch.