A7 Heating and Air Conditioning


A-7 Heating and Air Conditioning Part 2

Progress:

1. A vacuum door actuator is being tested. When vacuum is applied with a hand held vacuum pump, the door does not move and the reading on the vacuum gauge is zero. Technician A says that the door does not move because it is binding or obstructed. Technician B says that the door does not move because the actuator is defective. Who is correct?

[caption id="attachment_1488" align="aligncenter" width="233"] Click image for larger view
Full Size View[/caption] 2. When the A/C damper door switch is placed in the MAX A/C position, the compressor clutch does not engage. However, a test light illuminates when placed at pin 1 of the A/C damper door switch. Which of the following could be the cause?

3. The readings shown above are taken with the A/C system operating at an ambient (outside) temperature of 85°F. What do the readings indicate?

4. 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 conditon is:

5. All of the following are classifications of antifreeze EXCEPT:

6. When recovering refrigerant from an A/C system, how long should the technician wait after the recovery/recycling unit has been turned off to see if there is any residual pressure in the system?

7. Two technicians are discussing sight glass observations. Technician A says that if foam is seen in the sight glass, the refrigerant charge is low. Technician B says that if oil streaks are seen in the sight glass, the refrigerant charge is low. Who is correct?

8. 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?

9. A customer complains that when when attempting to parallel park his vehicle it stalls repeatedly only when the air conditioning is on. Technician A says that the power steering pressure switch is defective. Technician B says that there is a problem with the power steering pump. Who is correct?

10. What is the minimum system pressure necessary to leak test with an electronic leak detector?

11. A customer complains about a hissing noise coming from under the hood after turning off the car. A Technician says the noise is coming from the A/C system and is:

12. The following are all methods of orifice tube replacement EXCEPT:

13. A customer has a complaint of poor heat output. After checking the hoses running from the heater core and finding them both to be hot, Technician A says the problem could be a clogged heater core. Technician B says a mis-adjusted temperature control cable could be the problem. Who is correct?

14. While identifying an A/C system, Technician A says that when the high-side service port fitting is smaller than the one on the low side, the system uses R134a refrigerant. Technician B says that an accumulator located between the evaporator and compressor is an indication that the system has an orifice tube. Who is correct?

15. Low heater output can be caused by all of the following EXCEPT:

16. During A/C system operation, a knocking sound can be heard coming from the compressor. Technician A says that there could be internal compressor damage. Technician B says that the compressor mounting brackets and bushings should be checked. Who is correct?

17. When using an electronic refrigerant leak detector, all of the following should be observed EXCEPT:

18. An air conditioning check has uncovered a discharge in the system and compressor damage. Technician A says that after the repairs are made, to check the low-pressure cutoff switch. Technician B says lubricating oil is carried by the refrigerant through the system. Who is correct?

19. Which of the following is a true statement regarding R134a refrigerant?

20. To properly evacuate an A/C system, the vacuum pump should be operated a minimum of:

21. Technician A says that the pressure cycling switch is usually located on the accumulator. Technician B says that the refrigerant must be recovered from the system before the switch can be removed. Who is correct?

22. The inside of an EATC equipped vehicle never feels as cool as the temperature setting. The A/C system checks out OK, including the sensors. Technician A says the aspirator tube could be disconnected from the duct. Technician B says there could be an obstruction in the aspirator tube. Who is correct?

23. A vehicle with R134a refrigerant in the A/C system has a refrigerant leak. Technician A says that a propane gas leak detector should be used to find the location of the leak. Technician B says that an electronic leak detector should be used to check for leaks. Who is correct?

[caption id="attachment_1490" align="aligncenter" width="295"] Click image for larger view
Full Size View[/caption] 24. The cooling fan works on low speed but not on high speed. Which of the following could be the cause?

25. During an A/C system performance test, highside pressure was found to be excessive and the A/C compressor continued to run. Technician A says that the high-pressure cutout switch could be defective. Technician B says that there could be an air flow obstruction at the condenser. Who is correct?

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