GM Service Manual Online
For 1990-2009 cars only

The function of the Automatic Level Control (ALC) system is maintaining a constant trim height at the rear suspension when the vehicle is loaded beyond a predetermined amount. The ALC system is active with the vehicle ignition switch in the ON position. The system consists of the following components:

    • An automatic level control sensor
    • Air shocks
    • Automatic level control air lines
    • An automatic level control air compressor assembly, consisting of the following components:
       - Automatic level control air compressor motor and head
       - Automatic level control air compressor bracket
       - Automatic level control air dryer
       - Automatic level control Air dryer filter
       - Exhaust solenoid
       - Automatic level control air compressor relay
       - Automatic level control air compressor filter

Object Number: 303361  Size: SH

An inflator system is included as part of the overall ALC system. The function of the inflator system is to provide air under pressure up to 482 kPa (70 psi) to an automatic level control solenoid valve for the purpose of inflating items other than the vehicle air shocks, such as sports balls, bicycle tires, automobile tires, etc. The automatic level control solenoid valve and the automatic level control inflator air switch are located behind the passenger-side body-side trim panel. The inflator system is active with the vehicle ignition switch in the ON position. The inflator system consists of the following components:

    • An automatic level control solenoid valve
    • An automatic level control inflator air switch
    • An automatic level control timer relay
    • An accessory kit