- Symptoms - HVAC Systems - Automatic

Symptoms - HVAC Systems - Automatic

Important: The following steps must be completed before using the symptom tables.



1. Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) before using the Symptom Tables in order to verify that all of the following are true:

* There are no DTCs set.
* The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to:

* Air Delivery Description and Operation (Air Delivery Description and Operation)
* Air Temperature Description and Operation (Air Temperature Description and Operation)




Visual/Physical Inspection

* Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories (Component Tests and General Diagnostics).
* 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 steering wheel or passenger HVAC controls.
* The A/C compressor will not operate in cold outside air temperatures. Refer to Air Temperature Description and Operation (Air Temperature Description and Operation).
* The following conditions may cause window fogging:

- Wet carpet or mats
- High humidity
- Interior water leak
- 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 (Component Tests and General Diagnostics).


Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

* Air Conditioning Compressor Malfunction (Air Conditioning Compressor Malfunction)
* Blower Motor Malfunction (Blower Motor Malfunction)
* Leak Testing (Leak Testing)
* Defrosting Insufficient (Defrosting Insufficient)
* Noise Diagnosis - Blower Motor (Noise Diagnosis - Blower Motor)
* Noise Diagnosis - Air Conditioning (A/C) System (Noise Diagnosis - Air Conditioning (A/C) System)
* Odor Diagnosis (Odor Diagnosis)
* Noise Diagnosis - HVAC Module (Noise Diagnosis - HVAC Module)