ASE Heating & Air Conditioning Flashcards

What is the purpose of the orifice tube in an automotive A/C system?

Answer: Meters refrigerant flow into the evaporator

The orifice tube is a fixed metering device that restricts and meters refrigerant flow into the evaporator, causing a pressure drop.

A heater core that leaks coolant into the passenger compartment will MOST likely cause which symptom?

Answer: Sweet smell and fogged windows

A leaking heater core deposits coolant inside the cabin, producing a sweet antifreeze odor and leaving a film on the windshield.

What does a high reading on both the high-side and low-side A/C gauges MOST likely indicate?

Answer: Blocked or restricted condenser

A restricted condenser prevents heat rejection, causing both high-side and low-side pressures to rise above normal operating range.

Which component controls the blend of heated and cooled air entering the passenger cabin in a dual-zone climate system?

Answer: Blend door actuator

Blend door actuators position the blend door to mix heated air from the heater core and cooled air from the evaporator per thermostat settings.

What is the correct procedure before adding refrigerant to an A/C system that has been opened for repair?

Answer: Evacuate the system with a vacuum pump to remove moisture and air

Evacuating the system pulls moisture out and creates a vacuum to confirm the system holds pressure before charging with refrigerant.

Which sensor signal does the ECM primarily use to cycle the A/C compressor clutch on and off to protect the system?

Answer: A/C pressure transducer

The A/C pressure transducer sends system pressure data to the ECM, which disengages the compressor clutch if pressure is too high or too low.