VErifiEd And GrAdEd A+
A technician connects a scan tool to a late model vehicle to troubleshoot a problem in the ATC
system. The scan tool gives a fault of "data bus short to ground." Technician A says that the
problem could be a data wire rubbing against a sharp body component. Technician B says that
the problem could be a broken data wire. Who is correct? ✔✔ A Only
Any of these methods of R134a A/C system leak detection are acceptable EXCEPT:
A. Dye and black light
B. Electronic leak detector
C. Nitrogen and soapy water
D. Propane burner ✔✔ D. Propane burner
An airbag system needs to be disarmed during an evaporator core replacement. Technician A
says that it is necessary to remove power from the system prior to component removal.
Technician B says that the inflatable devices should be laid "face up" in a secure area after being
removed from a vehicle. Who is correct? ✔✔ Both A and B
An orifice tube performs any of these jobs in the A/C system EXCEPT:
A. Meters refrigerant into the evaporator core
B. Filters foreign particles
C. Separates the high side from the low side
D. Opens and closes to regulate pressure on the low side ✔✔ D. Opens and closes to regulate
pressure on the low side
A serpentine belt is being replaced and the tensioner will not snap back after being released.
Technician A says that the tensioner spring could be broken and the tensioner will need to be
,replaced. Technician B says that the idler pulley is jammed and will need to be replaced. Who is
correct? ✔✔ A Only
Technician A says that R-134a systems use mineral oil to lubricate the compressor. Technician B
says that R-12 systems use PAG oil to lubricate the compressor. Who is correct? ✔✔ Neither A
or B
Technician A says HVAC control panel directs the signal to the mode actuators to determine
where the air is discharged. Technician B says that some HVAC control panels contain logic
capabilities. Who is correct? ✔✔ Both A and B
A heater core is suspected to be restricted and causing the heater to not be warm enough.
Technician A says that a temperature drop test should be performed on the heater inlet and
outlet hoses. Technician B says that the heater system should create about 140°F air at the
vents. Who is correct? ✔✔ Both A and B
Any of these steps should be followed when replacing an automatic temperature control (ATC)
controller EXCEPT:
A. Disconnect the positive battery cable
B. Connect a ground strap to your wrist and connect to a metallic component
C. Use a battery maintainer while reprogramming the new controller
D. Disconnect the negative battery cable ✔✔ A. Disconnect the positive battery cable
Technician A says that the line exiting the condenser should be hotter than the line entering the
condenser. Technician B says that the suction line should be cold to the touch when the A/C
system is operating. Who is correct? ✔✔ B Only
Before replacing an HVAC electronic control panel, the technician should:
A. Remove the control cables from the vehicle
, B. Disconnect the negative battery cable
C. Disassemble the dash panel
D. Apply dielectric grease to the switch contacts ✔✔ B. Disconnect the negative battery cable
The compressor clutch will not disengage when the A/C control is switched to off. The most
likely problem is:
A. The A/C pressure cutoff switch is stuck open
B. The compressor clutch coil is shorter to ground
C. The low pressure switch has an open wire
D. The compressor coil feed circuit is shorted to voltage ✔✔ D. The compressor coil feed circuit
is shorted to voltage
What is the LEAST LIKELY condition that could cause a blower resistor thermal element to burn
up?
A. Tight blower motor bearing
B. Open blower motor winding
C. Wire rubbing a metal bracket
D. Blower motor fan blade rubbing the duct ✔✔ B. Open blower motor winding
An R-134a A/C system has a damaged service fitting. Technician A says the fitting needs to be
mid seated after the manifold hose adapter is installed in order to read A/C pressure. Technician
B says that the Schrader valve in the fitting can be replaced without recovering the refrigerant.
Who is correct? ✔✔ Neither A or B
A pulse width modulated electric cooling fan motor is being diagnosed. Technician A says that
the HVAC control module energizes these motors by signaling a fan control driver module.
Technician B says that these fans operate at two speeds. Who is correct? ✔✔ A Only