- Symptoms - HVAC Systems - Manual

SYMPTOMS

IMPORTANT: Review the system operation in order to learn the system functions. Refer to the following procedures:
- Air Delivery Description and Operation
- Air Temperature Description and Operation

Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the HVAC System.
- Inspect the system components which are easily accessible or visible for obvious damage or for conditions which could cause the symptom.
- Verify the A/C compressor clutch turns freely and is not seized.
- 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:
- A wet carpet
- High humidity
- An interior water leak
- A blocked drain tube to the A/C evaporator
- 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
- Blocked or damaged air vents

Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions.

Symptom List
Refer to one of the following symptom diagnostic procedures:
- HVAC Compressor Clutch Does Not Engage Compressor Clutch Does Not Engage
- HVAC Compressor Clutch Does Not Disengage Compressor Clutch Does Not Disengage
- Blower Motor Always On Blower Motor Always On
- Blower Motor Inoperative Blower Motor Inoperative
- Blower Motor Malfunction Blower Motor Malfunction
- Too Hot in Vehicle Too Hot In Vehicle
- Too Cold in Vehicle Too Hot In Vehicle
- Air Delivery Improper Air Delivery Improper
- Air Recirculation Malfunction Air Recirculation Malfunction
- Leak Testing in Heating, Ventilation and Air Conditioning
- Defrosting Insufficient in Heating, Ventilation and Air Conditioning Defrosting Insufficient
- Noise Diagnosis - Blower Motor in Heating, Ventilation and Air Conditioning Noise Diagnosis - Blower Motor
- Noise Diagnosis - Air Conditioning (A/C) System in Heating, Ventilation and Air Conditioning Noise Diagnosis - Air Conditioning (A/C) System
- Noise Diagnosis - HVAC Module in Heating, Ventilation and Air Conditioning Noise Diagnosis - HVAC Module
- Odor Diagnosis in Heating, Ventilation and Air Conditioning Odor Diagnosis