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.

Dimming Switch: The scan tool displays 0.0 to 16.0 volts, depending on the Dimming switch position.

Courtesy Lamp Switch: The scan tool displays Inactive/Active. The input of the courtesy lamp switch is displayed as Active when the courtesy lamps are on.

Headlamp Switch: The scan tool displays Inactive/Active. The input of the headlamp switch is displayed as active when the headlamps switch is On.

Park Lamp Switch: The scan tool displays On/Off. The input of the park lamp switch is displayed as On when the park lamps are command On.

Hi Beam On Switch: The scan tool displays Inactive/Active. The input of the high beam switch is displayed as active when the high beam headlamps are turned on.

Fog Lamp Switch: The scan tool displays Inactive/Active. The input of the fog lamp switch is displayed as active if the fog lamp switch is turned on.

Surveillance Mode Switch: The scan tool displays Inactive/Active. The input of the emergency vehicle interior lamp switch is displayed as active if the switch is turned to the off position.

Theater Dim 1 Ground: The scan tool displays Inactive/Active. The input of the theater dim 1 ground is displayed as active when the ground is present at the BCM for the theater dim lamps.

Theater Dim 2 Ground: The scan tool displays Inactive/Active. The input of the theater dim 2 ground is displayed as active when the ground is present at the BCM for the theater dim lamps.

Ambient Light Sensor Reference: The scan tool displays On/Off. This output of the BCM is displayed as On when the ambient light sensor voltage reference output is present.

Theater Dimming #1: The scan tool displays On/Off. This output of the BCM is displayed as On when the courtesy lamps are turned on.

DRL 1 (LT): The scan tool displays On/Off. This output of the BCM is displayed as On when the DRL lamps are turned on.

Headlamp Relay: The scan tool displays On/Off. This output of the BCM is displayed as On, if the headlamps are turned on.

Parklamp Relay: The scan tool displays On/Off. This output of the BCM is displayed as On, if the BCM commands the parklamps On.

Fog Lamp Relay: The scan tool displays On/Off. This output of the BCM is displayed as On, if the BCM commands the fog lamps on.

Backup Lamp Relay: The scan tool displays Inactive/Active. This output of the BCM is displayed as Active, if the BCM commands the backup lamps on.