GM Service Manual Online
For 1990-2009 cars only
Ambient Light Sensor: The scan tool displays 0.0 to 5.0 volts, depending on light intensity.

Backup Lamp Relay:  The scan tool displays Inactive/Active. This output of the BCM is displayed as active when the backup lamps are turned on.

Courtesy Switch: The scan tool displays ON/OFF. The input of the courtesy switch is displayed as ON when the courtesy lamps are command ON.

Courtesy Ground: The scan tool displays Present/Not Present. The input of the courtesy ground is displayed as Not Present when the ground for the courtesy lamps is not detected.

Driver Door Switch: The scan tool displays OPEN/CLOSED. The input of the driver door switch is displayed as OPEN when the driver door is open.

Door Jamb Switch: The scan tool displays OPEN/CLOSED. The input of the door jamb switch is displayed as OPEN when the any door is open.

Front Fog Lamp Relay: The scan tool displays ON/OFF. This output of the BCM is displayed as ON when the fog lamps are turned on.

Headlamp Switch: The scan tool displays Inactive/Active. The input of the Headlamp switch is displayed as active when the headlamp lamps are command ON.

Headlamps: The scan tool displays ON/OFF. This output of the BCM is displayed as ON, if the BCM commands the headlamps ON.

Inadvert. Power Output: The scan tool displays ON/OFF. This output of the BCM is displayed as ON when the Inadvert. power output is present.

Left Turn Signal:  The scan tool displays ON/OFF. This output of the BCM is displayed as ON, when the left front turn signal flashes or the DRL are activated.

LCM Lights on Chime: The scan tool displays ON/OFF. The input of the LCM Lights on chime is displayed as ON when the headlamps switch is ON.

LT Turning Signal Sw.: The scan tool displays ON/OFF. The input of the LT Turning Signal Sw. is displayed as ON if the turn signal switch is activated in the turn right position.

Park Brake Indicator Switch: The scan tool displays ON/OFF. The input of the park brake indicator switch is displayed as ON when the park brake is ON.

Park Lamps: The scan tool displays ON/OFF. This output of the BCM is displayed as ON, if the BCM commands the parklamps ON.

Right Turn Signal: The scan tool displays ON/OFF. This output of the BCM is displayed as ON when the right front turn signal flashes or the DRL are activated.

RT Turning Signal Sw.: The scan tool displays ON/OFF. The input of the RT Turning Signal Sw. is displayed as ON if the turn signal switch is activated in the turn right position.

Theater Dimming #1: The scan tool displays ON/OFF. This output of the BCM is displayed as ON, if the BCM commands the courtesy lamps ON.