ASE A7 HVAC Final

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?

• A low refriderant charge.
• A defective radiator cooling fan.

• A normal condition.
• A faulty compressore clutch relay.

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 Too much freon. Who is correct?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B

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?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

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 control modules that use temperature and pressure actuated sensors and switches. Who is correct?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

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?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

All of these are true about an air conditioner's evaporator EXCEPT:

• It removes humidity from the air.
• Refrigerant flows from the bottom to the top.
• Refrigerant enters the evaporator as a liquid.
• The refrigerant changes from a vapor to a liquid as it receives heat from the cabin air.

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?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

A compressor clutch coil is being tested. There is 12 volts at the connector and the ground is good. The resistance of the coil is OL . 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?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

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?

• Technician A only
• Technician B only
• Both Technician A and B
• Neither Technician A nor B

R134A Freon has a boiling point of

• -15 degrees F

• -30 Degrees F

• 15 Degrees F

• 212 Degrees F