ASE A7 Exam: Questions & Answers (Heating Air Conditioning)
Tech A says that evacuating the A/C system will remove air and moisture from the system. Tech B says
that evacuating an A/C system will remove dirt particles from the system. Who is right? - ANSWER:Tech A
Only
There is a growling or rumbling noise at the A/C compressor when the system is off and the engine is
running. The noise stops when the s is turned on. Tech A says that a bad compressor bearing could be
the cause. Tech B says that a bad compressor clutch bearing could be the cause. Who is right? -
ANSWER:Tech B Only
The reading shown above are taken with the A/C system operating at an ambient (outside) temperature
of 85F (29C). What do the readings indicate? - ANSWER:Low refrigerant level
Recovery/recycling equipment must have shutoff valves located within 12-in, (30cm) of the hoses'
service ends so that? - ANSWER:Refrigerant discharge can be kept to a minimum
When recovering refrigerant from an A/C system, how long should the tech wait after the
recovery/recycling unit has been turned off to see it there is any residual pressure in the system? -
ANSWER:5 Minutes
A system with a low pressure on the low side and heavy frost accumulation on the inlet side of the side
Thermostatic Expansion Valve (TXV) indicates a? - ANSWER:Clogged screen or TXV stuck closed
A blower motor only works on high speed. Which of the following causes is the MOST LIKELY? -
ANSWER:Defective blower resistor
A customer complains that when accelerating his car with the A/C on, the cold air flow from the dash
outlets shifts on the floor. Tech A says that this is caused by a faulty check in the vacuum reservoir. Tech B
says that this condition is due to a vacuum leak. Who is right? - ANSWER:Both A and B
When pressure testing the cooling system on a late-model gasoline engine vehicle, the pressure on the
tester drops but no leaks can be found in the engine compartment. Tech A starts the engine and, seeing
the pressure on the tester gauge increase says that there is an internal leak, a blown head gasket. Tech B
says that there cannot be an internal leak because the engine oil looks normal, not milky like it would be
if coolant were present, and there is no white smoke coming from the exhaust pipe. Who is right? -
ANSWER:Tech A Only
When identifying an A/C system, Tech A says that the accumulator located between the evaporator and
compressor is an indication that the system has an orifice tube. Tech B says that when the high-side
service port fitting is smaller than the one on the low side, the system uses R134a refrigerant. Who is
right? - ANSWER:Tech A Only
When troubleshooting an ATC system, the system responds when the ambient and in-vehicle
temperature sensors are heated and cooled. However, there is no response when the sun load sensor is
exposed to a light source. Tech A says that the problem is with the systems programmer. Tech B says that
the problem is with the sun load sensor. Who is right? - ANSWER:Tech B Only
, The following are all methods of orifice tube replacement EXCEPT? - ANSWER:Disconnect the liquid line
from the evaporator inlet line and, using a twisting motion to break free of the line, pull out the orifice
tube with an extractor tool
Tech A says when there is a "U" DTC, it should be repaired before any further diagnostics can be
performed. Tech B says "U" DTCs indicate there is nothing wrong with the A/C system? - ANSWER:Tech A
Only
A vehicle with R134a refrigerant in the A/C system has a refrigerant leak. Tech A says that a propane gas
leak tester should be used to find the location of the leak. Tech B says that an electronic leak detector
should be used to check for leaks. Who is right? - ANSWER:Tech B
Which of the following is a true statement regarding R134a refrigerant? - ANSWER:It requires a different
desiccant than R12
The compressor in an A/C system does not run. When a jumper wire is used to connect the battery-
positive terminal to the power connector, the compressor clutch engages. Tech A says that the clutch coil
is defective. Tech B says that the pressure cycling switch could be defective. Who is right? - ANSWER:Tech
B
The floor inside a vehicle is wet and there is a slimy film on the windows. Tech A says that the heater
core is leaking. Tech B says that the evaporator caser drain plug is clogged. Who is right? - ANSWER:Tech
A
During A/C system operation, a knocking sound can be heard coming from the compressor. Tech A says
that there could be internal compressor damage. Tech B says that the compressor mounting brackets
and bushings should be checked. Who is right? - ANSWER:Both A and B
All of the following could causer poor heater performance EXCEPT: - ANSWER:stuck open heater control
valve
During an A/C system performance test, the air temperature at the center outlet duct is warm to slightly
cool and the low and high-side pressures on the manifold gauge set are both low. All of the following
could be the cause of these symptoms EXCEPT: - ANSWER:Plugged condenser
What is the minimum system pressure necessary to leak test with an electronic leak detector? -
ANSWER:50 psi
Observing the data stream while operating a HVAC system on a ate model vehicle the counts for the
blend door change when the vehicle is moved outside the mid day sun. Tech A says there is an
intermittent problem with the blend door actuator that will eventually set a DTC. Tech B says that under
no circumstances should the counts change on the blend door motor. Who is right? - ANSWER:Neither A
or B
When diagnosing an ATC system, most of the system temperature sensors can be tested for? -
ANSWER:Resistance and voltage drop
During an A/C system performance test, high-side pressure was found to be excessive and the A/C
compressor continued to run. Tech A says that the high-pressure cutout switch could be defective. Tech B
says that there could be air flow obstruction at the condenser. Who is right? - ANSWER:Both A and B
Tech A says that evacuating the A/C system will remove air and moisture from the system. Tech B says
that evacuating an A/C system will remove dirt particles from the system. Who is right? - ANSWER:Tech A
Only
There is a growling or rumbling noise at the A/C compressor when the system is off and the engine is
running. The noise stops when the s is turned on. Tech A says that a bad compressor bearing could be
the cause. Tech B says that a bad compressor clutch bearing could be the cause. Who is right? -
ANSWER:Tech B Only
The reading shown above are taken with the A/C system operating at an ambient (outside) temperature
of 85F (29C). What do the readings indicate? - ANSWER:Low refrigerant level
Recovery/recycling equipment must have shutoff valves located within 12-in, (30cm) of the hoses'
service ends so that? - ANSWER:Refrigerant discharge can be kept to a minimum
When recovering refrigerant from an A/C system, how long should the tech wait after the
recovery/recycling unit has been turned off to see it there is any residual pressure in the system? -
ANSWER:5 Minutes
A system with a low pressure on the low side and heavy frost accumulation on the inlet side of the side
Thermostatic Expansion Valve (TXV) indicates a? - ANSWER:Clogged screen or TXV stuck closed
A blower motor only works on high speed. Which of the following causes is the MOST LIKELY? -
ANSWER:Defective blower resistor
A customer complains that when accelerating his car with the A/C on, the cold air flow from the dash
outlets shifts on the floor. Tech A says that this is caused by a faulty check in the vacuum reservoir. Tech B
says that this condition is due to a vacuum leak. Who is right? - ANSWER:Both A and B
When pressure testing the cooling system on a late-model gasoline engine vehicle, the pressure on the
tester drops but no leaks can be found in the engine compartment. Tech A starts the engine and, seeing
the pressure on the tester gauge increase says that there is an internal leak, a blown head gasket. Tech B
says that there cannot be an internal leak because the engine oil looks normal, not milky like it would be
if coolant were present, and there is no white smoke coming from the exhaust pipe. Who is right? -
ANSWER:Tech A Only
When identifying an A/C system, Tech A says that the accumulator located between the evaporator and
compressor is an indication that the system has an orifice tube. Tech B says that when the high-side
service port fitting is smaller than the one on the low side, the system uses R134a refrigerant. Who is
right? - ANSWER:Tech A Only
When troubleshooting an ATC system, the system responds when the ambient and in-vehicle
temperature sensors are heated and cooled. However, there is no response when the sun load sensor is
exposed to a light source. Tech A says that the problem is with the systems programmer. Tech B says that
the problem is with the sun load sensor. Who is right? - ANSWER:Tech B Only
, The following are all methods of orifice tube replacement EXCEPT? - ANSWER:Disconnect the liquid line
from the evaporator inlet line and, using a twisting motion to break free of the line, pull out the orifice
tube with an extractor tool
Tech A says when there is a "U" DTC, it should be repaired before any further diagnostics can be
performed. Tech B says "U" DTCs indicate there is nothing wrong with the A/C system? - ANSWER:Tech A
Only
A vehicle with R134a refrigerant in the A/C system has a refrigerant leak. Tech A says that a propane gas
leak tester should be used to find the location of the leak. Tech B says that an electronic leak detector
should be used to check for leaks. Who is right? - ANSWER:Tech B
Which of the following is a true statement regarding R134a refrigerant? - ANSWER:It requires a different
desiccant than R12
The compressor in an A/C system does not run. When a jumper wire is used to connect the battery-
positive terminal to the power connector, the compressor clutch engages. Tech A says that the clutch coil
is defective. Tech B says that the pressure cycling switch could be defective. Who is right? - ANSWER:Tech
B
The floor inside a vehicle is wet and there is a slimy film on the windows. Tech A says that the heater
core is leaking. Tech B says that the evaporator caser drain plug is clogged. Who is right? - ANSWER:Tech
A
During A/C system operation, a knocking sound can be heard coming from the compressor. Tech A says
that there could be internal compressor damage. Tech B says that the compressor mounting brackets
and bushings should be checked. Who is right? - ANSWER:Both A and B
All of the following could causer poor heater performance EXCEPT: - ANSWER:stuck open heater control
valve
During an A/C system performance test, the air temperature at the center outlet duct is warm to slightly
cool and the low and high-side pressures on the manifold gauge set are both low. All of the following
could be the cause of these symptoms EXCEPT: - ANSWER:Plugged condenser
What is the minimum system pressure necessary to leak test with an electronic leak detector? -
ANSWER:50 psi
Observing the data stream while operating a HVAC system on a ate model vehicle the counts for the
blend door change when the vehicle is moved outside the mid day sun. Tech A says there is an
intermittent problem with the blend door actuator that will eventually set a DTC. Tech B says that under
no circumstances should the counts change on the blend door motor. Who is right? - ANSWER:Neither A
or B
When diagnosing an ATC system, most of the system temperature sensors can be tested for? -
ANSWER:Resistance and voltage drop
During an A/C system performance test, high-side pressure was found to be excessive and the A/C
compressor continued to run. Tech A says that the high-pressure cutout switch could be defective. Tech B
says that there could be air flow obstruction at the condenser. Who is right? - ANSWER:Both A and B
