Circuit/System Verification
WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Ignition ON, activate the air suspension inflator switch. The switch indicator should illuminate and the air compressor should activate supplying air pressure to the air accessory port.