NCE PRACTICE EXAM

2023 Edition

ASE defines heating and air conditioning as an individual service area. This area includes all components and systems both mechanical and electronic that are related to a vehicle’s heating and air conditioning system.

Tests.com's ASE A7 Practice Test was written by Dr. John Kershaw, an ASE test prep expert: ASE test question developer; ASE Certified Master Technician; ASE Master Truck Technician; and Auto Industry Technical Instructor. Dr. Kershaw was among the first to receive ASE certification in 1972.

For complete test practice, flash cards, exam review and testing tips, check out:

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AC System Service, Diagnosis and Repair

1.	This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following statements are correct regarding an air conditioning performance test, EXCEPT:
		a. Road debris can clog the condenser fins reducing system performance.
		b. To avoid outside odor, operate AC System in RECIRC rather than FRESH mode.
		c. Passenger-side floor being wet is one symptom of a clogged evaporator drain line.
		d. Obstructions of the cabin air filter may cause insufficient air circulation.
To avoid evaporator odor, you operate AC System in FRESH mode not RECIRC mode. Incorrect answer. Please choose another answer.

AC System Service, Diagnosis and Repair

2.	During an air conditioning performance test, the technician notices that the compressor outlet is hot. Technician A says this is a normal condition. Technician B says the air conditioning system is overcharged. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Technician A is correct. Technician B is wrong because an overcharge will cause the compressor outlet to be cold. Incorrect answer. Please choose another answer.

AC System Service, Diagnosis and Repair

3.	Technician A says when the condenser airflow is restricted the pressure is high in both high and low lines. Technician B says an indication of low refrigerant is when both the high and low sides show low pressure. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Both technicians are correct. Courtesy of Toyota Incorrect answer. Please choose another answer.

AC System Service, Diagnosis and Repair

4.	Which of the problems listed below will cause the manifold gauge readings shown in the illustration?
		a. Refrigerant overcharge
		b. Low refrigerant
		c. Expansion valve stuck closed
		d. Restricted condenser airflow
When both the low and high sides are high, this indicates a refrigerant overcharge or restricted condenser. Courtesy of Toyota Incorrect answer. Please choose another answer.

Refrigeration System Diagnosis and Repair - Compressor and Clutch

5.	This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following tasks are performed when replacing an AC compressor, EXCEPT:
		a. Reuse all mounting brackets
		b. Use new gaskets and seals
		c. Use the same or equivalent compressor
		d. Reuse same compressor oil
You never reuse compressor oil. Incorrect answer. Please choose another answer.

Refrigeration System Diagnosis and Repair - Compressor and Clutch

6.	A compressor clutch will not engage. Power and ground at the clutch coil are good. Which of the following is the MOST likely cause?
		a. Low refrigerant
		b. Locked-up compressor
		c. Incorrect air gap
		d. Bad pressure cycling switch
With power and a ground, the clutch should have worked unless the gap is too wide, and is the most likely cause. Incorrect answer. Please choose another answer.

Refrigeration System Diagnosis and Repair - Compressor and Clutch

7.	On a manual air conditioning system without automatic control, the compressor clutch does not operate. Technician A says there is a failed compressor thermal protector. Technician B says there is an incorrectly adjusted temperature door. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Technician A is correct because if thermal protector fails the B+ path to the compressor clutch is open and it is the most likely cause. Technician B is wrong because temperature door position does not affect compressor operation on a manual system. Incorrect answer. Please choose another answer.

Refrigeration System Diagnosis and Repair - Compressor and Clutch

8.	Using a DMM (digital multimeter), a technician measures 12 volts at the clutch coil, but it will not engage. Technician A says a bad clutch coil could be the cause. Technician B says a bad clutch coil ground could be the cause. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Both technicians are correct. Incorrect answer. Please choose another answer.

Refrigeration System - Evaporator, Condenser and Related Components

9.	This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following issues regarding a receiver/dryer are correct, EXCEPT:
		a. Clogged filter can cause higher than normal pressure
		b. Saturated desiccant can cause a blockage due to freezing
		c. You install a new desiccant bag on some systems before charging the system.
		d. Evacuating system removes moisture from a saturated receiver/dryer
System evacuation will not remove all of the moisture in the desiccant of a receiver/dryer due to its enclosure. Incorrect answer. Please choose another answer.

Refrigeration System - Evaporator, Condenser and Related Components

10.	This question has the word EXCEPT. For this question, look for the choice that could NOT cause the described situation. Read the entire question carefully before choosing your answer. All of the following are true regarding the expansion valve, EXCEPT:
		a. When stuck closed, pressure on high side is low and pressure on low side is high.
		b. It can fail in the open position as a result of debris in the system.
		c. It can seize in the closed position due to a lack of lubricant.
		d. With moisture in the system, ice can form and cause blockage.
When the expansion valve is stuck closed, both high and low pressure are low. Incorrect answer. Please choose another answer.

Refrigeration System - Evaporator, Condenser and Related Components

11.	Technician A says all air conditioning connections use a gasket or O-ring to seal the system. Technician B says when replacing O-rings you lubricate the O-ring with the correct refrigerant oil to prevent nicks and ease installation. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Both technicians are correct. Incorrect answer. Please choose another answer.

Refrigeration System - Evaporator, Condenser and Related Components

12.	A concern of intermittent AC cooling is being diagnosed. The gauge set shows intermittently high and low side pressure gauge readings and the high side intermittently drops to 100 psi. Which of the following is the MOST likely cause?
		a. Stuck expansion valve
		b. Overcharged A/C System
		c. Compressor internal leak
		d. Damaged compressor reed valve
A stuck expansion valve is the most likely cause based on both high and low pressures being low. Incorrect answer. Please choose another answer.

Heating and Engine Cooling Systems Diagnosis and Repair

13.	Technician A says a defective thermostat can cause the engine to operate at too cold of a temperature. Technician B says if the thermostat is stuck closed it can make a pinging or banging sound. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Both technicians are correct. Incorrect answer. Please choose another answer.

Heating and Engine Cooling Systems Diagnosis and Repair

14.	Two technicians are describing heater diagnosis. Technician A says one heater hose is hot to the touch and the other hose is cold when the heater core is functioning okay. Technician B says the upper radiator hose should be at engine operating temperature, which is very hot to the touch. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Technician A is wrong because both heater hoses should be hot. Technician B is right because the upper radiator hose should be too hot to hold. Incorrect answer. Please choose another answer.

Heating and Engine Cooling Systems Diagnosis and Repair

15.	What high-side and low-side pressure gauge readings would a technician find if the condenser fan were inoperative?
		a. High-side high and low-side low
		b. High-side low and low-side high
		c. Both high-side high and low-side are low
		d. Both high-side high and low-side are high
An inoperative condenser fan can cause a high high-side and high low-side reading. Answer option A is wrong because high high-side and low low-side pressure generally indicates a restriction evaporator air flow. B is wrong because high low-side and low high-side pressure indicate internal compressor damage. C is wrong because when both high and low-side pressure are low you can have the following faults: low charge, suction line obstruction, clogged orifice tube, stuck closed TXV valve and restricted line from the condenser to the evaporator. Incorrect answer. Please choose another answer.

Heating and Engine Cooling Systems Diagnosis and Repair

16.	Which of the following conditions is the MOST likely cause of a vehicle overheating?
		a. Electric cooling fan runs all the time
		b. Restricted heater core
		c. Thermostat stuck open
		d. Clogged radiator
A clogged radiator is the most likely cause because a restriction of any kind in the cooling system will cause an engine to overheat. Answer option A is not a most likely cause because a constantly running cooling fan will not cause overheating. B is not a most likely cause because a restriction heater core will cause no heat but not necessarily cause an engine overheat. C is also wrong because a stuck open thermostat will not cause overheating. Incorrect answer. Please choose another answer.

Operating Systems and Related Controls Diagnosis and Repair

17.	Technician A says a misadjusted temperature door could cause a poor heat complaint. Technician B says a defective resistor trio can cause a no high blower condition. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Technician A is right because a misadjusted blend door affects heat. Technician B is wrong because the high blower is controlled by the high blower relay not the resistor trio. Incorrect answer. Please choose another answer.

Operating Systems and Related Controls Diagnosis and Repair

18.	Technician A says a radiator should always be inspected for leaks before installing a rebuilt engine. Technician B says overheating during slow in-town driving can be caused by an electric cooling fan fault. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Both technicians are correct. Incorrect answer. Please choose another answer.

Operating Systems and Related Controls Diagnosis and Repair

19.	The heater blows out only cold air at operating temperature. Technician A says a stuck closed thermostat could be the cause. Technician B says the cooling system could be low on coolant. Who is right?
		a. A only
		b. B only
		c. Both A and B
		d. Neither A nor B
Technician B is right because when the system is low on coolant there is insufficient material to transfer the heat. Technician A is wrong because a stuck thermostat causes overheating resulting in high temperatures and plenty of heat. Incorrect answer. Please choose another answer.

Operating Systems and Related Controls Diagnosis and Repair

20.	If a cooling system operates at too cool an operating temperature, the engine will do which of the following?
		a. Have more torque
		b. Have less efficiency
		c. Have ignition detonate
		d. Produce higher emissions
A specific engine temperature is needed to consume all of the pollutants. Incorrect answer. Please choose another answer.