Car Air Conditioning Repair Flashcards
7 cards from real Air Conditioning Repair practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Car Air Conditioning Repair flashcards as text
Which electrical component engages and disengages the AC compressor on most conventional systems?
Answer: Electromagnetic clutch
The electromagnetic clutch magnetically couples the compressor pulley to the compressor shaft when energized, allowing the compressor to be driven by the serpentine belt only when needed.
A manifold gauge shows high-side pressure of 350 psi and low-side pressure of 10 psi on a hot day. What does this pattern suggest?
Answer: Blocked orifice tube or expansion valve
Extremely high discharge pressure combined with very low suction pressure is a classic sign of a restriction (blockage) in the metering device, starving the evaporator of refrigerant.
What is the correct procedure for adding refrigerant to a car AC system that is slightly low?
Answer: Add refrigerant as a liquid to the low-side port with the engine running and AC on
Refrigerant is added as a gas (or low-pressure liquid from an inverted can) to the low-side service port with the engine running and AC on max, never to the high side.
What is a common symptom of a failed or slipping AC compressor clutch?
Answer: AC does not cool at all and compressor pulley spins freely without engaging the hub
A failed clutch coil or worn friction disc allows the pulley to spin without driving the compressor, so the system produces no pressure differential and no cooling.
How does an orifice tube system differ from a TXV system in refrigerant metering?
Answer: An orifice tube is a fixed restriction; a TXV dynamically modulates flow based on superheat
The orifice tube is a simple fixed-diameter metering device, while the TXV continuously adjusts refrigerant flow to maintain a set superheat at the evaporator outlet.
After recharging, a technician notices the AC vent temperature is warmer than expected despite correct refrigerant charge. What component should be inspected next?
Answer: Condenser fins for dirt and blockage
A clogged or bent condenser prevents adequate heat rejection, raising refrigerant temperature and reducing the system's ability to produce cold air even with a proper charge.
What is the role of the AC pressure cycling switch found in some orifice tube systems?
Answer: It cycles the compressor on and off to prevent evaporator freeze-up
The pressure cycling switch monitors low-side pressure and cuts the compressor when pressure drops to the freeze point, then restarts it once pressure rises, regulating evaporator temperature.