GM Service Manual Online
For 1990-2009 cars only

Use the scan tool data display values and definitions information in order to assist in diagnosing vehicle malfunctions. Compare the vehicles actual scan tool data display with the typical data value in the table. Use the data in order to aid in understanding the nature of the concern when the vehicle data display does not match the typical data values. Refer to Scan Tool Data List .

The typical scan tool data values were taken from a known good vehicle under the following conditions:

    • The ignition switch is in the ON position.
    • The windshield wiper/washer switch is OFF.
Washer Switch: The body control module (BCM) uses this input to determine if the wash switch is pressed. If it is pressed, the BCM commands the wiper micro relay ON and keeps it ON until 2 wipe cycles have completed after the switch has been released.

Wiper Delay Input: The BCM uses this input to determine if it should command the wiper micro relay ON, and the length of the delay between wipes. The scan tool displays 0 volts when the windshield wiper switch is OFF.

Wiper Park Switch: The BCM uses this input to determine if the wipers are approaching the park position. The scan tool displays Active when the BCM detects ground on the windshield wiper motor park switch signal circuit.

Wiper Relay Cmd.: This output displays whether or not the BCM, or any other voltage source, is providing voltage for the wiper micro relay. ON is displayed when the BCM detects voltage on the windshield wiper switch signal 2 circuit.