Circuit Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2005 Isuzu Ascender, 2005 GMC Envoy XUV, 2005 GMC Envoy XL, 2005 GMC Envoy, and 2005 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The system relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids and to the ABS pump motor. When the relay contacts close, the EBCM monitors the voltage supplied to the valve solenoids and compares this voltage to monitored ignition voltage.