Vehicle HVAC Systems
Exam Materials
Course Introduction
Vehicle HVAC Systems explores the principles, design, and operation of heating, ventilation, and air conditioning systems in automobiles and other vehicles. This course covers the fundamentals of thermodynamics, refrigeration cycles, fluid mechanics, and the key components involved in regulating cabin temperature and air quality. Students will learn about system layout, diagnostics, maintenance, modern advancements such as automatic climate control, eco-friendly refrigerants, and integration with vehicle electronics. Emphasis is placed on compliance with industry standards, energy efficiency, and troubleshooting techniques to ensure optimal performance and passenger comfort.
Recommended Textbook
Todays Technician Automotive Heating Air Conditioning Classroom Manual and Shop Manual 5th
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13 Chapters
631 Verified Questions
631 Flashcards
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Chapter 1: Heating and Air Conditioning - History and the Environment
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48 Verified Questions
48 Flashcards
Source URL: https://quizplus.com/quiz/44057
Sample Questions
Q1) The most common gas in the earth's atmosphere is oxygen.
A)True
B)False
Answer: False
Q2) Name some effects of ultraviolet radiation.
Answer: Ultraviolet radiation can be damaging to living organisms,causing sunburn; skin cancer; damage to eyes,including cataracts; and premature aging and wrinkling of the skin.UV radiation can also break down the food chain by destroying plankton in the ocean and depriving certain species of their natural food.Plant life and crops can also be harmed or destroyed by excessive radiation.
Q3) <i>Technician A</i> says ozone is both created and destroyed by the action of UV radiation on oxygen molecules.<i>Technician B</i> says chlorine is the major gas causing the destruction of ozone.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Answer: C
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Chapter 2: Temperature and Pressure Fundamentals
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Sample Questions
Q1) All of the following statements about heat transfer are true,EXCEPT:
A) Molecular motion is transmitted to molecules that have less motion.
B) Some of the molecules give up their energy to other molecules that have more energy.
C) Heat flows from matter at a higher temperature to matter at a lower temperature.
D) Heat never flows from low-temperature matter to high-temperature matter.
Answer: B
Q2) As heat energy is added to a liquid,the speed of its molecules increases.
A)True
B)False
Answer: True
Q3) All of the following are true of voltage drops EXCEPT:
A) Voltage drop is the conversion of electrical energy into another form of energy.
B) Corrosion in a circuit does not cause a voltage drop.
C) All of the source voltage in a circuit must be dropped.
D) Voltage drop can be measured with a voltmeter.
Answer: B
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4
Chapter 3: Engine Cooling and Comfort Heating
Systemsdiagnosis and Service of Engine Cooling and Comfort Heating Systems
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57 Verified Questions
57 Flashcards
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Sample Questions
Q1) <i>Technician A </i> says one should always follow OEM specifications for a radiator pressure cap rating.<i>Technician B </i> says a defective radiator pressure cap could cause overcooling.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Answer: A
Q2) The engine cooling system is designed to remove about 80 percent of the total engine heat.
A)True
B)False
Answer: False
Q3) What is the difference between the vertical flow and cross flow radiators?
Answer: In the vertical flow radiator,coolant flows from the top tank to the bottom tank.In the cross flow radiator,coolant flows from one side tank to the other side tank.
Q4) What can cause overcooling?
Answer: A defective thermostat that is stuck open or opens prematurely.
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Chapter 4: Air-Conditioning System Operating
Principlesthe Manifold and Gauge Set
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50 Verified Questions
50 Flashcards
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Sample Questions
Q1) What is the drying agent in the receiver-drier or accumulator known as?
Q2) Accumulators are used with expansion valve systems.
A)True
B)False
Q3) What component is used and how does liquid refrigerant lower passenger compartment temperature?
Q4) The metering device changes high-pressure liquid to
A) a low-pressure vapor.
B) a low-pressure liquid.
C) a high-pressure liquid.
D) any of the above, depending on the outside air temperature.
Q5) Explain why high pressure must be maintained in the condenser.
Q6) The receiver-dryer is located on the low-pressure side of the system.
A)True
B)False
Q7) Where in the system is the receiver dryer located?
A) on the inlet to the condenser.
B) on the outlet of the evaporator.
C) on the outlet of the condenser.
D) none of the above.
Page 6
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Page 7
Chapter 5: Refrigerant System Componentsservicing
System Components
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44 Flashcards
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Sample Questions
Q1) Why must the condenser outlet be at the bottom?
Q2) Once the refrigerant from the air conditioning system has been recovered,which of the following should the technician do?
A) Check the purity of the refrigerant in the recovery tank.
B) Change the recovery unit fiters.
C) Record the amount of refrigerant oil removed from the system.
D) Change the receiver-drier.
Q3) The EPA requires the replacement of hoses or seals during the retrofit of a vehicle from R-12 to R-134a.
A)True
B)False
Q4) An H valve is often referred to as a block valve.
A)True
B)False
Q5) The compressor separates the low side from the high side of the system. A)True B)False
Q6) Removing spring lock fittings on refrigerant lines requires a special tool.
A)True
B)False Page 8
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Page 9
Chapter 6: Refrigerant System Servicing and
Testingair-Conditioning System Servicing and Testing
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51 Verified Questions
51 Flashcards
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Sample Questions
Q1) Refrigerant vapors are lighter than air.
A)True
B)False
Q2) R-134a and R-12 systems use the same refrigerant oil.
A)True
B)False
Q3) System malfunctions cannot be detected by visual inspection.
A)True
B)False
Q4) <i>Technician A</i> says that the recommended oil for most R-134a systems is PAG oil.<i>Technician B</i> says that the recommended oil for R-12 systems is mineral-based oil.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q5) What two factors determine the amount of moisture removed from an air conditioning system?
Q7) List popular methods of refrigerant leak detection. Page 10
Q6) What are the sources of refrigerant system contamination?
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Chapter 7: Diagnosis of the Refrigeration System
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53 Verified Questions
53 Flashcards
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Sample Questions
Q1) Name some ways in which air could enter the air conditioning system.
Q2) What are most restrictions in a refrigerant system are caused by?
Q3) What effect would a low-side restriction have on a system and how would it be detected?
Q4) What is the symptom of a refrigerant system that is overcharges with refrigerant?
Q5) On a refrigerant system there is heavy frost on the expansion vave inlet and low-side pressure is well below normal.<i>Technician A</i> says that the expansion valve is stuck in the open position could be the cause.<i>Technician B</i> says that a restricted expansion valve inet screan could be the cause.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q6) High-side restrictions can cause extremely high temperatures.
A)True
B)False
Q7) By comparison what are the different pressure characteristics of R-134a refrigerant compared to R-12 refrigerant?
Page 12
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Chapter 8: Compressors and Clutches
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Sample Questions
Q1) A vehicle returns to the shop for a repeat failure of the compressor system due to compressor clutch slippage and overheating.Which of the following is the most likely cause?
A) A loose drive belt
B) High resistence in the comprssor clutch electrical circuit.
C) A low refrigerant charge level.
D) A faulty compressor clutch diode.
Q2) <i>Technician A</i> says when the compressor oil is drained,the oil can be reused if it looks good.<i>Technician B</i> says the type of new oil installed or added is not important as long as the compressor has enough oil.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q3) Some compressor noise is normal during regular operation.
A)True
B)False
Q4) Explain the concept of reciprocating pistons as used in automotive air conditioning compressors.
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Chapter 9: Case and Duct Systems
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52 Verified Questions
52 Flashcards
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Sample Questions
Q1) Mode door adjustments are being discussed.<i>Technician A</i> says the vacuum motor can be adjusted for motor stroke.<i>Technician B</i> says a cable can be adjusted for full movement of the door.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q2) <i>Technician A</i> says that a liquid antimicrobial deodorizer and disinfectant is used to eliminate odors in duct systems.<i>Technician B</i> says when a musty odor develops the odor causing mold and mildew must be eradicated.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q3) How are pollen and dust particles stopped from entering the passenger compartment.
Q4) Describe how you would bypass the vacuum system to test an inoperative vacuum motor.
Q5) How does the blend door create the desired in-vehicle temperature?
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Chapter 10: System Controlsdiagnosis and Service of
System Controls
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49 Verified Questions
49 Flashcards
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Sample Questions
Q1) Explain what is meant by this sentence: "The change in resistance value of each sensor is inversely proportional to a temperature change."
Q2) On an automatic temperature control system that will not hold the temperature set at the control panel,what should the technician do first?
A) Replace the incar temperature sensor.
B) Replace the the temperature mode door actuator.
C) Refer to the appropriate manufacuterer service information.
D) Recover and recharge the A/C system.
Q3) If blower motor speed control is provided by resistors,the motor will have three windings.
A)True
B)False
Q4) The blower motor in Figure has blower motor speed M2,M3,and High speed.But does not run in either LOW or M1.Which of the faults listed below could be the cause:
A) Faulty blower motor.
B) Faulty blower motor relay.
C) Faulty Heater A/C control assembly.
D) Faulty resistor block.
Page 15
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Chapter 11: Retrofit and Future Trends
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45 Flashcards
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Sample Questions
Q1) XH7 and XH9 desiccants are compatible with R-134a and R-12 refrigerants.
A)True
B)False
Q2) Retrofits are being discussed.<i>Technician A</i> says the procedure involves replacing the refrigerant.<i>Technician B</i> says new service fittings must be installed.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q3) Under what conditions should system oil be charged directly into the compressor?
Q4) What is the advantage of placing the vehicle in a draft-free work area?
Q5) <i>Technician A</i> says flushing the air conditioning before retrofitting is a common procedure.<i>Technician B</i>says each component should be removed and flushed individually.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q6) When should a saddle clamp access valve be installed?
Page 16
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Chapter 12: Extenssion 1: Shop Safety
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54 Verified Questions
54 Flashcards
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Sample Questions
Q1) What is OSHA?
Q2) Explain safety hazards that may result from wearing improper footgear in the shop.
Q3) Describe some of the procedures that should be followed when working with gasoline.
Q4) <i>Technician A</i> says 'Right-to-Know" laws are designed to insure employee awareness of the characteristics of chemicals and solvents existing in the workplace.<i>Technician B</i> says a list of all of the hazardous substances found in the workplace must be posted in the shop.Who is correct?
A) A only
B) B only
C) Both A and B
D) Neither A nor B
Q5) Explain what carbon monoxide is and where it comes from in the automotive industry.
Q6) Explain,in the proper sequence,the steps performed to remove a battery from a vehicle.
Q7) What action must be taken immediately when a chemical gets in the eyes.
Q8) What does the word toxicity mean?
Q9) What type of injury is caused by improper lifting techniques.
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Chapter 13: Extenssion 2: Typical Shop Procedures and Tools
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Sample Questions
Q1) Refrigerant identifiers are being discussed.<i>Technician A </i> says a refrigerant identifier will display R-12 if the refrigerant is 90% CFC-12 by weight.<i>Technician B </i> says a refrigerant identifier will display R-134a if the refrigerant is 98% HFC-134a by weight.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q2) What are the four basicemployee obligations?
Q3) <i>Technician A </i> says a manifold and gauge sets is a manifold block complete with gauges and charging hoses.<i>Technician B </i> says a can tap is a device used to pierce,dispense,and seal small cans of refrigerant.Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B
Q4) A vacuum pump is used to remove refrigerant from the system.
A)True
B)False
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