Heating & AC part descriptions
A - F
AC/Heater Control Module
The AC/heater control module is a computer that automates and controls the operation of a vehicle’s HVAC system. A faulty module can cause improper heating, cooling, or air distribution. Diagnosing issues involves reviewing fault codes and potentially updating the module’s software based on manufacturer technical service bulletins.
Air Conditioner (A/C) Relay
The Air Conditioner (A/C) Relay is an electrical component that controls power to the A/C compressor and clutch when the system is activated. It can cause intermittent A/C operation or warm air from vents if faulty. Testing is recommended before replacement, as other issues may mimic relay failure.
Air Conditioning Accumulator/Receiver-Drier
The Air Conditioning Accumulator/Receiver-Drier removes moisture and filters particles from the refrigerant. It ensures only dry, gaseous refrigerant enters the compressor, preventing corrosion and system blockages. This part is typically replaced when faulty or during major AC repairs.
Air Conditioning Compressor
The air conditioning compressor pumps refrigerant through the AC system to keep the car cool. It is usually driven by the engine’s drive belt. Signs of a failing compressor include the AC blowing warm air, strange noises, refrigerant leaks, and the check engine light coming on.
Air Conditioning Condenser
The air conditioning condenser is located behind the grille. It functions like a radiator, cooling hot refrigerant as air passes through its tubes and fins. The condenser transforms gaseous refrigerant into liquid, enabling the AC to cool the cabin effectively.
Air Conditioning Dryer
The air conditioning dryer, also known as a receiver/dryer or accumulator, removes moisture from the AC system’s refrigerant. It contains desiccant materials that absorb water, preventing corrosion and freezing of the AC components. The dryer also filters out debris and serves as a refrigerant reservoir.
Air Conditioning Evaporator
The air conditioning evaporator receives cold refrigerant gas, absorbs heat from passing air, and blows cooled air into the passenger compartment through dashboard vents. Symptoms of a failing evaporator include weak or no cool air and strange odours.
Air Conditioning Hose
An air conditioning hose is a high-pressure rubber hose with aluminum fittings that transports refrigerant between the A/C compressor and other A/C components. It can fail due to wear, causing reduced cooling and visible damage like cracks or leaks. Replacing a bad A/C hose requires a licensed mechanic.
Air Conditioning Refrigerant
Air Conditioning Refrigerant: A substance that absorbs heat from a vehicle’s cabin, enabling the air conditioning system to cool the interior. Common types include R134a and R1234yf. Low refrigerant levels can cause lack of cooling, compressor clutch cycling, and A/C warning lights. Leaks require professional evacuation and recharging.
Cabin Air Filter
The cabin air filter prevents dust, pollen, and other debris from entering the passenger compartment through the climate control system. It catches dirt, smoke, bacteria, allergens, and exhaust gases, improving air quality inside the car. Signs of a bad filter include musty smells, reduced airflow, and longer window clearing times.
Expansion Valve
The expansion valve regulates the flow of refrigerant into the evaporator, ensuring optimal cooling performance. When faulty, it can result in reduced cooling efficiency, with the primary symptom being air from the AC that isn’t sufficiently cold.