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HVAC Questions and Answers |
New One | Grade A+
thermostat Ans: Is a temperature dep endent valve that opens and closes according to the engine coolant temperature to regulate the flow of coolant through the radiator and back to the engine Coolant Pump Ans: Are mechanically controlled devices that circulate coolant through the radiator and back to the engine. Radiator Ans: Is a liquid to air heat exchanger that reduces coolant temperature by transferring heat from the radiator to the outside air Degas bottle Ans: Is attached to the radiator. It hold excess or overflowing coolant, removes air from the cooling system, allows for expansion and system pressurization, and used to replenish coolant in the system.
Coolant Bypass Solenoid Valve Ans: Used to provide a second path for coolant to flow between the engine block and thermostat housing. ( PCM opens the the solenoid valve to increase coolant flow through the block to reduce pressure and temperature fluctuations ) Coolant shut off solenoid valve Ans: Used to control coolant flow to the thermostat housing, coolant pump, engine block, cylinder heads, heater core, turbocharger, transmission oil cooler, and engine oil cooler. The 2014 C-max uses a catalytic converter exhaust manifold with coolant passages to: Ans: raise coolant temperature to expedite passenger compartment heating on hybrid electric vehicles The heater core is an air to liquid heat exchanger similar to a radiator? Ans: False Heater core Ans: Is a liquid to air heat exchanger, air passes through the heater core, heat is transferred from the engine coolant to the air inside the climate control housing.
the vehicle is remotely started the customer has activated the remote cabin preconditioning feature The cabin heater diverter valve is controlled by the PCM an is used to : Ans: isolate the heater circuit form the engine cooling circuit to improve heater performance. On hybrid vehicles, the cabin heater coolant pump will provide coolant to engine components when the engine is running. Ans: true which supplemental heating system uses a heating element to warm the air in the HVAC housing? Ans: both, electric booster heater, auxiliary heater assembly the electric booster heater system used on the 2014 fiesta will activate two relays to power how many heating elements inside the electric booster heater? Ans: 3 selecting the highest heat setting on the climate control module in on condition that must be met to operate the electric booster heater system Ans: true
the auxiliary heater assembly uses what module to control the electrical supply to the heating elements? Ans: AHCM Latent heat of vaporization occurs in the refrigerant system when: Ans: refrigerant changes state from a low-pressure liquid to a low-pressure vapor inside the evaporator. Latent heat of condensation occurs in the refrigerant system when: Ans: the condenser extracts heat from the refrigerant into the outside air A day when the outside temperature is 21C with 30% humidity feels hotter than a day with 32C temperature at 5% humidity Ans: true what causes a liquid to change into a vapor? Ans: heat changing the pressure of a liquid change its:
what style of electrically powered compressor is used on hybrid and electric vehicles? Ans: scroll what is the main difference between a variable scroll and fixed scroll compressor? Ans: a variable scroll uses a control valve to adjust output capacity. which of the following statements does not apply to the evaporator? Ans: the refrigerant leaves the evaporator as a liquid the A/C system is divided into two sides: a low-pressure or suction side and a high-pressure or discharge side. what component separates the two sides? Ans: TXV or the fixed orifice tube A/C Cycling Switch Ans: The A/C cycling switch monitors low side pressure at the accumulator to prevent evaporator freezing. Blower motor Ans: blower motor circulates air through the heater core and the evaporator core housing
on vehicles equipped with a variable displacement compressor the PCM uses evaporator temperature sensor information to prevent icing of the evaporator core by cycling the compressor on and off Ans: false The high-pressure cutoff switch is mounted on the discharge line between the compressor and the condenser. Ans: true which style of actuator uses a single power feed and four low side circuits connected to the climate control module to control the position of the actuator door? Ans: stepper motor The A/C pressure transducer is used by the PCM to monitor what pressure? Ans: both refrigerant section pressure refrigerant discharge pressure The climate control system uses vehicle speed information to: Ans: stabilize the outside temperature reading.
when the defrost setting is selected, the recirculated function is activated on the air inlet door actuator will only allow recirculated air into the passenger compartment. Ans: false when the PCM receive an A/C request signal, it uses what information to determine if the A/C compressor should be engaged? Ans: - refrigerant pressure, engine coolant or cylinder head temperatures
- ambient air, and evaporator discharge temperatures
- throttle position sensor signal
- all of the above* the auto start-stop system may automatically restart the engine when: Ans: - blower speed is increased
- the power windows are operated.
- an additional vehicle accessory is plugged into a power outlet
- all of the above * to operate the climate control system during remote start, what should the climate control setting be placed in? Ans: both, AUTO mode, last setting mode
During remote start the climate controlled seat system will activate the cooled seat function when ambient air temperature is greater than: Ans: 27C ( 80F ) When the factory remote start feature is activated and the DATC system is in auto mode, which of the following readings is not used to determine climate control demand Ans: Evaporator temperature When the factory remote start feature is activated, the rear defroster, heated mirrors, and heated or climate controlled seats do not automatically activate at moderate temperatures. Ans: true what actuator does the rear climate control system use to reach the requested air temperature? Ans: auxiliary temperature blend door the climate control system adjusts the auxiliary door position to direct airflow to: Ans: both , roof panel registers , floor ducts the rear climate control system uses an auxiliary air inlet door actuator to direct outside air into the passenger compartment.
which of the following statements does not apply to the heated seat systems? Ans: the rear heated seat system is controlled by two rear heated seat modules what module controls the operation of the rear heated seat system Ans: rear heated seat module what control devices activate the front heated seat system? Ans: FCIM FDIM SWITCHES all of the above* which module is used by the climate controlled seats system to heat or cool the rear seats? Ans: PCSM- 2 the cooling feature used in the climate controlled seats system only operates when the vehicle's A/C system is cooling the vehicle Ans: false climate controlled seats are available in the second row seating position.
Ans: true which of the following devices provide an interface to control the operation of the front and rear climate controlled seats? Ans: FDIM HVAC module RHVAC all of the above* which module is used by the climate controlled seats system to hear or cool the front seats? Ans: DCSM which of the following symptoms could cause a no flow condition through the heater core outlet hose? Ans: both the heater core is clogged with contaminants an air pocket in the heater core when conducting a cooling system pressure test, the pressure gauge should hold at maximum pressure for approximately how long?
which of the following components cannot be checked using active commands? Ans: cabin heater coolant temperature sensor the high voltage battery must be full charged when diagnosing the cabin coolant system. Ans: true The cabin heater coolant temperature sensor provides coolant temperature information to what module. Ans: PCM The 2010 F-super Duty electric booster supplemental heater system will not operate when there are Continuous Memory Diagnostic trouble codes ( CMDTCs ) related to the function of what system? Ans: charging the electric booster supplemental heater system used on the 2010 F-super duty will not operate if the generator is operating above 75% capacity. Ans: false which conditions must be met when diagnosing the electric booster supplemental heater system used on the 2013 escape or 2014 fiesta?
Ans: both, engine coolant temperature is below 60C ( 140 F ) ambient air temperature is below 10c ( 50F ) the electric booster supplemental heater system is an engine coolant supplied device that heats the passenger compartment rapidly in cases of low ambient temperatures. Ans: false which component in the electric booster supplemental heater system uses a current PID to verify that the current level at the component is above 50 amps Ans: Auxiliary heater control module ( AHCM ) it is not necessary to add dye after flushing the refrigerant system because a new suction accumulator or receiver/drier containing a fluorescent dye wafer is installed as part of the flushing procedure. Ans: true what conditions must be met when using an infrared refrigerant leak detector or dual mode refrigerant gas and UV Dye leak detector? Ans: Both
- refrigerant pressure should be between 413-551 kpa ( 50.9 - 79.91 psi )
Ans: high when recording refrigerant pressure you should only take refrigerant pressure readings when the compressor is engaged. Ans: true When a restriction is in the liquid and discharge line between the condenser and high pressure service port, high side pressure is: Ans: high An undercharged refrigerant system will show high side pressure being normal to low and low side pressure: Ans: low when connected to the A/C system, the Neutronic quick detect A/C Sealant detector kit is designed to: Ans: mimic an A/C leak The sealant detection kit and refrigerant analyzer are used to prevent damage to recovery equipment. Ans: true
The refrigerant analyze will illuminate a red FAIL LED if purify level of refrigerant is below what percentage by weight? Ans: 98% When performing a A/C cooling coil coating treatment which of the following components should be removed if they are exposed to the blower motor airflow? Ans: blower motor blower motor resistor blower motor speed controller all of the above* Environmental orders are caused by an external source and are only detected when Ans: both the vehicle windows are open the climate control system is drawing fresh air into the vehicle when storing refrigerant, do not exceed what percentage of the cylinder's refill capacity? Ans: 60%
