HVAC 3

A noisy compressor is being discussed. Technician A says that the air conditioning system could be low on lubricating oil. Technician B says that the system could be overcharged. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technician A nor B

Both pressure gauge needles are oscillating rapidly. Which component is the most likely cause?

• The compressor (reed valves)

• The orifice tube (clogged)

• The expansion valve (stuck closed)

• The drier (desiccant bag is saturated with moisture)

A service technician is replacing a water (coolant) pump. Technician A says that the used coolant should be properly disposed of or kept for recycling. Technician B says that the used coolant should be reused to refill the cooling system after the repair is completed. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technicians A nor B

A customer complained of lack of heat from the heater. A check of the cooling system shows that the upper radiator hose is not getting hot. Technician A says that the thermostat may be defective (stuck open). Technician B says that the cause could be a defective (always engaged) thermostat cooling fan. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technicians A nor B

A lack of heat from the heater is being discussed. Which is the most likely cause?

• A partially clogged radiator

• Hoses reversed to the heater core

• A partially clogged heater core

• A defective water pump

The temperature gauge approaches the red part of the temperature gauge (260°F. or 127°C.) if driven at slow speeds but does not overheat if driven at highway speeds. What is the most likely cause?

• Low coolant level

• Incorrect antifreeze/water mixture

• Defective water (coolant) pump

• Inoperative cooling fan

A "pop" is heard from the radio speakers occasionally when the defroster of air conditioning is selected. Technician A says that the compressor clutch clamping diode may be blown. Technician B says that the air conditioning compressor clutch may have a poor electrical ground. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technician A nor B

A reduced amount of airflow from the air conditioning vents is being discussed Technician A says that the evaporator could be clogged as a result of a small refrigerant leak causing oil to trap and hold dirt. Technician B says that the blower motor ground connection could have excessive voltage drop. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technician A nor B

Technician A says that an electrical open in the low pressure switch can prevent the compressor from working. Technician B says that the compressor may not operate at low outside temperatures depending on the pressure sensed by the low pressure switch. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technician A nor B

Technician A says that the voltage to the air conditioning compressor may be turned off when some vehicles are accelerating rapidly. Technician B says that a fault in the power steering pressure switch could prevent the air conditioning compressor from operating. Which technician is correct?

• Technician A only

• Technician B only

• Both Technicians A and B

• Neither Technician A nor B