Circuit/System Description
WARNING: This page is about a different car, the 2008 Isuzu i-370, 2008 Isuzu i-290, 2008 GMC Canyon, and 2008 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
The solenoid and pump motor relay are located within the electronic brake control module (EBCM). The solenoid relay supplies battery voltage to all of the valve solenoids. Three pump motor relays supply battery positive voltage to the pump motor when the EBCM commands the pump motor on.