A7 Heating and Air Conditioning Quiz

1. A CCOT system has a high high side. Technician A says to suspect the thermostatic expansion valve. Technician B says this system contains an orifice tube. Who is correct?
2. All these statements are true about a throttle position sensor EXCEPT:
3. A vehicle's air conditioning performance is reduced at low speeds and stop lights, but cools at highway speeds. Which of these is MOST likely the cause of this condition?
4. Two technicians are discussing an inoperative electric blend door in an automatic air conditioning system. Technician A says to inspect the blend door's wiring an connections for an open circuit. Technician B says to troubleshoot this circuit with a test light. Who is correct?
5. A squeal is heard only when the compressor clutch first engages. Technician A says this is caused by a loose serpentine belt. Technician B says this is caused by a worn clutch pulley bearing. Who is correct?
6. Two technicians are discussing a CCOT air conditioning system. Technician A says the temperature cycling clutch switch contains a bulb placed on the inlet port of the evaporator core. Technician B says a pressure cycling switch is located on the low side of the system. Who is correct?
7. A frozen spot is noticed in the center of the condenser. Technician A says a frozen spot on a component or connection indicates a restriction in the system. Technician B says this is caused by a clogged orifice tube. Who is correct?
8. A technician is diagnosing a vehicle's air conditioning system. The vehicle has good engine performance, but the air conditioner is blowing warm air only. A yellow substance is noticed around the evaporator case drip tube. Technician A says this is coolant leaking from the heater core. Technician B says this is fluorescent dye leaking from the evaporator core. Which technician is MOST likely correct?
9. R 134a Refrigerant:
10. Two technicians are discussing electric cooling fans and air conditioning performance. Technician A says electric fans regulate refrigerant temperatures more precisely than belt driven fans do. Technician B says electric cooling fans are controlled by temperature and pressure actuated switches. Who is correct?
11. An air conditioning system with a variable displacement compressor has poor performance in high demand situations. All of these could be the cause EXCEPT:
12. Technician A says the clutch relay protects the control head from the clutch circuit's high current. Technician B says open clutch relay windings result in compressor clutch engagement at all times. Who is correct?
13. All of these are true about an air conditioner's evaporator EXCEPT:
14. Technician A says refrigerant flows from the top of the condenser to the bottom. Technician B says a restriction in a condenser can cause damage to the compressor. Who is correct?
15. A blower motor operates only in high speed. Technician A says there could be a short in the motor's power feed. Technician B says it may have a faulty blower motor resistor. Who is correct?
16. A compressor clutch coil is being tested. There are 12 volts at the connector and the ground is good. The resistance of the coil is 0.00 Ohms. Technician A says the coil has an open in it's windings. Technician B says the clutch coil has a short and has failed the resistance test. Who is correct?
17. A vehicle's air conditioner blows cold air at normal speeds, but warm air while sitting at stop lights. The LEAST likely cause of this condition is:
18. The carpet is wet on the passenger's side of a vehicle. Technician A says this may be caused by a leaking heater core. Technician B says this could be caused by a clogged evaporator case drain tube. Who is correct?
19. The in-cabin temperature sensor is suspected for an air conditioner's poor performance. Technician A says the in-cabin temperature sensor is a NTC that should be tested for resistance with an ohmmeter. Technician B says the aspirator may be disconnected from the vent system. Who is correct?
20. A (TXV) thermostatic expansion valve system blows cold air for five minutes and then goes warm. Technician A says this condition is caused by a low refrigerant charge. Technician B says this condition is caused by moisture in the system. Who is correct?
Please select an answer