Exam 54: Heating and Air Conditioning

More than half of the heat that is in a vehicle's passenger compartment comes from solar radiation.

Technician A says hybrid vehicles have an electric water pump to circulate coolant through the heater core when the engine is stopped. Technician B says hybrid vehicles have a hot coolant storage tank to provide heat for the passenger compartment when the engine is shut down. Who is correct?

The customer says that there is no heat in the passenger compartment. Technician A says a disconnected engine vacuum hose could not cause the problem. Technician B says a seized blend door could cause the problem. Who is correct?

The use of any refrigerant that contains ____________________ substances, such as propane and butane, is illegal and dangerous.

R-134a systems are required to be fitted with ____________________ service fittings throughout the system.

What is the purpose of the thermostatic switch?

Before 1994, most manufacturers used _____ as a refrigerant.

The heater control valve is often called the water flow valve.

Which statement is true?

The U.S. Clean Air Act of 1990 requires that all service technicians who work on A/C systems must be certified in proper refrigerant recovery and recycling.

Humans find high relative humidity more comfortable than low  humidity.

Before 1994, most automotive A/C systems used a refrigerant called ____________________.

What is the purpose of an A/C system's electromagnet clutch?

Which of these statements is true?

The heater core is part of the engine's ____________________ system.

What is the purpose of a blend door?

The evaporator is located _____.

Thermal expansion valves are being discussed. Technician A says the TEV regulates the refrigerant flow to the evaporator by balancing the inlet flow to the outlet temperature. Technician B says the TEV is closed when the temperature at the outlet of the evaporator is high. Who is correct?

Why does condensed water drip from the air-conditioning system?

Federal safety standards do not require that all motor vehicles be equipped with passenger compartment heating and windshield defrosting systems.