GM Service Manual Online
For 1990-2009 cars only

Data

Battery Voltage Signal: The scan tool displays the battery system voltage received by the module.

Ambient Light Sensor: The scan tool displays the output voltage of the ambient light sensor based on the intensity of light detected. As the light intensity increases, the sensor displayed voltage decreases. In the LIGHT state, a low voltage, not less than 1.75 volts, is present and the DRL will be ON. In the DARK state, a high voltage, up to 4.9 volts, is present and the headlamps will be ON.

Dimming Potentiometer: The scan tool displays the voltage value indicating the position of the I/P dimmer switch. The scan tool displays 4 volts when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON or the I/P dimmer switch is in the FULL DIM position. The scan tool displays 0 volts when either the park lamps or the headlamps are turned ON and the I/P dimmer switch is in the FULL BRIGHT position.

Inputs

Ignition Off/Run/Crank: The scan tool displays the position of the ignition switch. The scan tool displays Active when the ignition switch is in the RUN or CRANK position.

Ignition 1 Run/Crank: The scan tool displays the position of the ignition switch. The scan tool displays Active when the ignition switch is in the RUN or CRANK position.

Driver Door Ajar Sw.: The scan tool displays the position of the driver door ajar switch. The scan tool displays Door Closed when the door is closed and Door Ajar when the door is open or ajar. The BCM uses this data in controlling the operation of the courtesy lamps and door ajar warning.

Passenger Door Ajar Sw.: The scan tool displays the position of the passenger door ajar switch. The scan tool displays Door Closed when the door is closed and Door Ajar when the door is open or ajar. The BCM uses this data in controlling the operation of the courtesy lamps and door ajar warning.

High Beam Select Switch: The scan tool displays the position of the high beam select switch. The scan tool displays Active when the switch is used to activate the high beams.

Headlamp On Switch: The scan tool displays the position of the headlamp switch. The scan tool displays Active when the headlamp switch is in the ON position. The BCM uses this data in controlling the operation of the headlamps.

Headlamp Off Switch: The scan tool displays the position of the headlamp switch. The scan tool displays Active when the headlamp switch is in the ON position. The BCM uses this data in controlling the operation of the headlamps.

Front Fog Lamp Switch: The scan tool displays the position of the front fog lamp switch. The scan tool displays ACTIVE when the switch is pressed. The BCM uses this data in controlling the operation of the front fog lamps.

Courtesy Lamp Switch: The scan tool displays the position of the courtesy lamp switch. The scan tool displays ACTIVE when the switch is activated. The BCM uses this data in controlling the operation of the courtesy lamps.

Dome Lamp Overide Switch: The scan tool displays the position of the dome overide switch. The scan tool displays On when the switch is pressed. The BCM uses this data in controlling the operation of the courtesy lamps.

Cargo Lamp Switch: The scan tool displays the position of the cargo lamp switch. The scan tool displays ACTIVE when the switch is pressed. The BCM uses this data in controlling the operation of the cargo lamp.

Hazard Lamp Switch: The scan tool displays the position of the hazard lamp switch. The scan tool displays ACTIVE when the switch is pressed. The BCM uses this data in controlling the operation of the hazard lamps.

Park Lamp Switch: The scan tool displays the position of the park lamp switch. The scan tool displays ON when the park lamp switch is in the ON position. The BCM uses this data in controlling the operation of the park lamps.

Park Brake Switch: The scan tool displays the position of the park brake pedal. The scan tool displays Applied when the park brake is engaged closing the switch. The BCM uses this data in controlling the operation of the park brake indicator, the reminder chime feature and the DRL system.

Front Wipers Active: The scan tool displays the status of the front wipers. The scan tool displays Yes after approximately the first 3 cycles of the wiper blades. The BCM uses this data in controlling the headlamps during wiper activated headlamp (WAH) mode.

Outputs

Inadvertent Power Cmd. 1: The scan tool displays the state of the inadvertent power battery rundown protection feature of the BCM. The scan tool displays On when all inadvertent power circuits are functioning normally.

LF Turn/Hazard Lamp Command: The scan tool displays the commanded state of the left front turn/hazard lamp. The scan tool displays ON when the BCM activates the left front turn/hazard supply voltage circuit.

LR Turn/Hazard Lamp Command: The scan tool displays the commanded state of the left rear turn/hazard lamp. The scan tool displays ON when the BCM activates the left rear turn/hazard supply voltage circuit.

RF Turn/Hazard Lamp Command: The scan tool displays the commanded state of the right front turn/hazard lamp. The scan tool displays ON when the BCM activates the right front turn/hazard supply voltage circuit.

RR Turn/Hazard Lamp Command: The scan tool displays the commanded state of the right rear turn/hazard lamp. The scan tool displays ON when the BCM activates the right rear turn/hazard supply voltage circuit.

DRL Status: The scan tool displays the commanded state of the daytime running lamps (DRL). The scan tool displays ON when the BCM activates the DRL mode.

Headlamp Relay: The scan tool displays the commanded state of the headlamp relay. The scan tool displays ON when the BCM grounds the headlamp relay to activate the headlamps.

High Beam Relay Command: The scan tool displays the commanded state of the high beam relay. The scan tool displays On when the BCM has activated the high beam relay to illuminate the high beam headlamps.

Park Lamps Signal: The scan tool displays the commanded state of the park lamp relay. The scan tool displays ON when the BCM activates the park lamp relay to illuminate the park lamps.

Courtesy Lamp Output: The scan tool displays the commanded state of the BCM to activate the courtesy lamps. The scan tool displays ON when the BCM energizes the courtesy lamps supply voltage circuit to illuminate the courtesy lamps.

Fog Lamp Relay Cmd.: The scan tool displays the commanded state of the fog lamp relay. The scan tool displays ON when the BCM energizes the fog lamp relay to activate the fog lamps.