Retrieving Diagnostic Trouble Codes
WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
Connect scan tool to the Data Link Connector (DLC), located under left side of dash. Turn ignition on, engine off. Using scan tool, retrieve DTCs. If HVAC system DTCs are present, perform appropriate test under DIAGNOSTIC TESTS. If no DTCs are present, diagnose by symptom. See SYMPTOM TEST INDEX table under SYMPTOM TESTS.