GM Service Manual Online
For 1990-2009 cars only

Scan Tool Parameter

Data Display

Units Displayed

Typical Data Value

Operating Conditions: Ignition in the ON position. Bright light applied to the DRL ambient light sensor. Park brake not set. Headlamp switch in the OFF position. IP Lamp switch in the OFF position. Interior lamp defeat switch in the OFF position. Fog lamp switch in the OFF position.

Ambient Light Sensor

Data List

Volts

2.1 volts

Ambient Light Sensor

Inputs

Active/Inactive

Inactive

Ambient Light Sensor Relay

Outputs

Off/On

On

Backlight Dimming

Data List

Percent

0

Backlight Dimming

Outputs

Off/On

Off

Courtesy Lamp Switch

Inputs

Active/Inactive

Inactive

Dimming Switch

Data List

Volts

0

DRL Relay

Outputs

Off/On

On

Fog Lamp Relay

Outputs

Off/On

Off

Fog Lamp Switch

Inputs

Active/Inactive

Inactive

High Beam Input

Data List

Volts

0

Headlamp Relay

Outputs

Off/On

Off

Headlamp Switch

Inputs

Active/Inactive

Inactive

High Beam Low Level

Inputs

Active/Inactive

Active

High Beam High Level

Inputs

Active/Inactive

Inactive

Inadvertent Power Relay

Outputs

Off/On

On

Interior Lamp Switch

Inputs

Active/Inactive

Inactive

Park Break Switch

Inputs

Active/Inactive

Inactive

Park Lamp Relay

Outputs

Off/On

Off

Park Lamp Monitor

Inputs

Active/Inactive

Inactive

Theater Lighting

Outputs

Off/On

Off