ASE AUTOMOBILE TECHNICIAN A7 –
HEATING & AIR CONDITIONING
PRACTICE EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. A customer complains that the A/C blows warm air at idle but cools while
driving. What is the most likely cause?
A. Low refrigerant charge
B. Faulty evaporator temperature sensor
C. Inoperative condenser fan
D. Restricted expansion valve
Answer: C
Rationale: At idle, airflow depends on the condenser fan; if it is
inoperative, high-side pressure rises and cooling is poor.
2. Which refrigerant oil is commonly used with R-134a systems?
A. Mineral oil
B. PAG oil
C. Ester oil only
D. Vacuum pump oil
Answer: B
Rationale: PAG oil is specified for most R-134a automotive A/C systems.
3. A low-pressure cycling switch opens when system pressure is too low to:
A. Increase cooling capacity
B. Protect the compressor
C. Increase refrigerant flow
, D. Reduce condenser pressure
Answer: B
Rationale: The switch prevents compressor damage from lack of
lubrication due to low refrigerant.
4. Frost forming on the suction line usually indicates:
A. Overcharged system
B. Restricted airflow across condenser
C. Low refrigerant or restricted expansion device
D. Faulty pressure switch
Answer: C
Rationale: Low pressure at the evaporator can cause refrigerant to boil
too rapidly and freeze moisture.
5. Which component removes moisture from the refrigerant?
A. Compressor
B. Expansion valve
C. Receiver-drier/accumulator
D. Condenser
Answer: C
Rationale: The desiccant in the drier or accumulator absorbs moisture.
6. A blend door stuck in the heat position will cause:
A. No airflow
B. Cold air only
C. Warm air regardless of A/C operation
D. High system pressure
Answer: C
Rationale: The blend door directs air through the heater core, adding
heat.
7. Which tool is used to detect refrigerant leaks electronically?
A. Manifold gauge set
B. UV lamp
C. Electronic leak detector
D. Vacuum pump
, Answer: C
Rationale: Electronic detectors sense refrigerant vapor in the air.
8. A compressor clutch that will not engage could be caused by:
A. Excess refrigerant
B. Low system pressure
C. Restricted condenser
D. Overheated evaporator
Answer: B
Rationale: The low-pressure switch opens and prevents clutch
engagement.
9. What happens if the A/C system is overcharged?
A. Low head pressure
B. Improved cooling
C. High head pressure and poor cooling
D. No effect
Answer: C
Rationale: Too much refrigerant reduces condenser efficiency and raises
pressure.
10.The purpose of evacuating an A/C system is to:
A. Add oil
B. Remove refrigerant
C. Remove air and moisture
D. Test pressure switches
Answer: C
Rationale: Evacuation boils off moisture and removes non-condensable
gases.
11.Which component meters refrigerant into the evaporator?
A. Condenser
B. Compressor
C. Expansion valve/orifice tube
D. Accumulator
Answer: C
HEATING & AIR CONDITIONING
PRACTICE EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. A customer complains that the A/C blows warm air at idle but cools while
driving. What is the most likely cause?
A. Low refrigerant charge
B. Faulty evaporator temperature sensor
C. Inoperative condenser fan
D. Restricted expansion valve
Answer: C
Rationale: At idle, airflow depends on the condenser fan; if it is
inoperative, high-side pressure rises and cooling is poor.
2. Which refrigerant oil is commonly used with R-134a systems?
A. Mineral oil
B. PAG oil
C. Ester oil only
D. Vacuum pump oil
Answer: B
Rationale: PAG oil is specified for most R-134a automotive A/C systems.
3. A low-pressure cycling switch opens when system pressure is too low to:
A. Increase cooling capacity
B. Protect the compressor
C. Increase refrigerant flow
, D. Reduce condenser pressure
Answer: B
Rationale: The switch prevents compressor damage from lack of
lubrication due to low refrigerant.
4. Frost forming on the suction line usually indicates:
A. Overcharged system
B. Restricted airflow across condenser
C. Low refrigerant or restricted expansion device
D. Faulty pressure switch
Answer: C
Rationale: Low pressure at the evaporator can cause refrigerant to boil
too rapidly and freeze moisture.
5. Which component removes moisture from the refrigerant?
A. Compressor
B. Expansion valve
C. Receiver-drier/accumulator
D. Condenser
Answer: C
Rationale: The desiccant in the drier or accumulator absorbs moisture.
6. A blend door stuck in the heat position will cause:
A. No airflow
B. Cold air only
C. Warm air regardless of A/C operation
D. High system pressure
Answer: C
Rationale: The blend door directs air through the heater core, adding
heat.
7. Which tool is used to detect refrigerant leaks electronically?
A. Manifold gauge set
B. UV lamp
C. Electronic leak detector
D. Vacuum pump
, Answer: C
Rationale: Electronic detectors sense refrigerant vapor in the air.
8. A compressor clutch that will not engage could be caused by:
A. Excess refrigerant
B. Low system pressure
C. Restricted condenser
D. Overheated evaporator
Answer: B
Rationale: The low-pressure switch opens and prevents clutch
engagement.
9. What happens if the A/C system is overcharged?
A. Low head pressure
B. Improved cooling
C. High head pressure and poor cooling
D. No effect
Answer: C
Rationale: Too much refrigerant reduces condenser efficiency and raises
pressure.
10.The purpose of evacuating an A/C system is to:
A. Add oil
B. Remove refrigerant
C. Remove air and moisture
D. Test pressure switches
Answer: C
Rationale: Evacuation boils off moisture and removes non-condensable
gases.
11.Which component meters refrigerant into the evaporator?
A. Condenser
B. Compressor
C. Expansion valve/orifice tube
D. Accumulator
Answer: C
