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

ALC Status

BCM

Off/On

Varies with light level

Ambient Light Sensor

BCM

Volts

Varies

Backup Lamp Relay Cmd.

BCM

Off/On

Off

Day/Night Status

BCM

Day/Night

Varies with light level

DRL Status

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 ON Switch

BCM

Inactive/Active

Inactive

High Beam Relay Command

BCM

Off/On

Off

High Beam Select Switch

BCM

Inactive/Active

Inactive

Inadvert Power CMD

BCM

Off/On

Off

Inadvert Power Signal

BCM

Inactive/Active

Inactive

Interior Light Command

BCM

Off/On

Off

Interior Lights Dimmed Command

BCM

Percentage

Varies

IP Dimmer Switch

BCM

Volts

Varies

Left Turn Signal Switch

BCM

Inactive/Active

Inactive

LF Turn Lamp/DRL Status

BCM

Off/On

Off

Low Beam Relay Command

BCM

Off/On

Off

LR Turn/Stop Lamp Status

BCM

Off/On

Off

Park Brake Switch

BCM

Off/On

Off

Park Lamp Relay Cmd

BCM

Off/On

Off

Park Lamp Switch

BCM

Off/On

Off

RF Turn Lamp/DRL Status

BCM

Off/On

Off

Right Turn Signal Switch

BCM

Inactive/Active

Inactive

RR Turn/Stop Lamp Status

BCM

Off/On

Off

Stop Lamp Relay Command

BCM

Off/On

Off