Important: The following steps must be completed before using the symptom tables.
- Perform the
Diagnostic System Check - Vehicle
before using the Symptom Tables in order to verify that all of the following are true:
• | There are no DTCs set. |
• | The control module(s) can communicate via the serial data link. |
- Review the system operation in order to familiarize yourself with the system functions. Refer to the following information:
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to
Checking Aftermarket Accessories
.
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
- Verify the A/C compressor clutch turns freely and is not seized.
- Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
- The A/C compressor will not operate in cold outside air temperatures. Refer to
Air Temperature Description and Operation
.
- The following conditions may cause window fogging:
• | Blocked A/C evaporator drain tube |
• | Maximum passenger capacity |
• | Blocked body pressure relief valves |
- Inspect the air distribution system for causes of reduced air flow:
• | Obstructed or dirty passenger compartment air filter, if equipped |
• | Blocked or damaged air inlet or outlet vents |
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections
.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: