GM Service Manual Online
For 1990-2009 cars only

Body Control Module (BCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON/Engine OFF/Doors, Trunk and Hood Closed/No Switches ON/Vehicle in PARK or NEUTRAL

Auto Headlamp Disable

BCM

Inactive/Active

Inactive

Ambient Light Status

BCM

Day/Night/Unknown/Invalid

Varies with light level

Ambient Light Sensor

BCM

Volts

Varies

Backup Lamps

BCM

Off/On

Off

DRL Relay Command

BCM

Off/On

Varies with light level

Flash to Pass Switch

BCM

Inactive/Active

Inactive

Front Fog Lamp Relay Command

BCM

Off/On

Off

Front Fog Lamp Switch

BCM

Inactive/Active

Inactive

Hazard Lamp Switch

BCM

Inactive/Active

Inactive

Headlamp OFF Switch

BCM

Off/On

On

Headlamp Switch

BCM

Inactive/Active

Inactive

High Beam Relay Command

BCM

Off/On

Off

High Beam Select Switch

BCM

Inactive/Active

Inactive

Left Turn Signal Switch

BCM

Inactive/Active

Inactive

LF Turn Signal

BCM

Off/On

Off

LR Turn Signal

BCM

Off/On

Off

Low Beam Relay Command

BCM

Off/On

Off

Park Lamp Relay Cmd

BCM

Off/On

Off

Park Lamp Switch

BCM

Off/On

Off

Right Turn Signal Switch

BCM

Inactive/Active

Inactive

RF Turn Signal

BCM

Off/On

Off

RR Turn Signal

BCM

Off/On

Off

Stop Lamp Switch Status

BCM

Counts

Varies

Stop Lamp Relay Command

BCM

Off/On

Off