How to Check Your Car’s Air Conditioning System ?
Problem Symptoms Table
Before replacing or repairing air conditioning components, first determine if the malfunction is due to the refrigerant charge, air flow or compressor.
Use the table below to help you find the cause of the problem. The numbers indicate the priority of the likely cause of the problem. Check each part in order.
How to Diagnose Your Car’s Air Conditioning System?
| Symptom | Suspect area |
| No blower operation | 1. Blower fuse |
| 2. Blower relay | |
| 3. Blower motor | |
| 4. Blower motor resistor | |
| 5. Blower speed control switch | |
| 6. Wire harness | |
| 1. Engine coolant capacity | |
| 2. Heater control assembly | |
| 3. Temp actuator | |
| No compressor operation | 1. Refrigerant capacity |
| 2. A/C fuse | |
| 3. Compressor | |
| 4. A/C pressure transducer | |
| 5. A/C pressure switch | |
| 6. Evaporator temperature sensor | |
| 7. Wire harness | |
| No cool comes out | 1. Refrigerant capacity |
| 2. Refrigerant pressure | |
| 3. Drive belt | |
| 4. Compressor | |
| 5. A/C pressure transducer | |
| 6. Evaporator temperature sensor | |
| 7. A/C switch | |
| 8. Heater control assembly | |
| 9. Wire harness | |
| Insufficient cooling | 10. Temperature actuator |
| 1. Refrigerant capacity | |
| 2. Drive belt | |
| 3. Compressor | |
| 4. Condenser | |
| 5. Expansion valve | |
| 6. Evaporator | |
| 7. Refrigerant lines | |
| 8. A/C pressure transducer | |
| 9. Heater control assembly | |
| No engine idle-up when A/C switch ON | 1. Engine ECM |
| 2. Wire harness | |
| No air inlet control | 1. Heater control assembly |
| 2. Intake actuator | |
| No mode control | 1. Heater control assembly |
| 2. Mode actuator | |
| 3. Intake actuator | |
| No cooling fan operation | 1. Cooling fan fuse |
| 2. Fan motor | |
| 3. Engine ECM | |
| 4. Wire harness |