Important: Complete the following steps before using the symptom tables:
- Perform
Diagnostic System Check - HVAC Systems - Automatic
before using the Symptom Tables in order to verify that all
of the following conditions are true:
1.2. | The control modules can communicate via the serial data link. |
- Review the system operation in order to become familiar with the system
functions. Refer to the following procedures:
Visual/Physical Inspection
- Inspect for aftermarket devices which can affect the operation of the
HVAC System. Refer to
Checking Aftermarket Accessories
in Wiring Systems.
- Inspect the accessible and the visible system components for obvious
damage or for conditions which can cause the symptom.
- Verify the A/C compressor clutch turns freely and is not seized.
- Verify that the customer is using the correct key in order to enable
personalization and is not activating the auxiliary HVAC controls.
- The A/C compressor will not operate in cold ambient air temperatures.
Refer to
Air Temperature Description and Operation
.
- The following conditions may cause window fogging:
- | A wet carpet or wet floor mats |
- | A blocked A/C evaporator drain tube |
- | Maximum passenger capacity |
- | Blocked body pressure relief valves |
- Inspect the air distribution system for causes of reduced airflow:
• | An obstructed or dirty passenger compartment air filter, if equipped |
• | Blocked or damaged air vents |
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions.
Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems.
Symptom List
Refer to the following diagnostic procedures: