GM HVAC and Climate Control Flashcards

What refrigerant is used in most modern GM vehicle HVAC systems produced after 2021?

Answer: R-1234yf

GM transitioned to R-1234yf refrigerant in newer models due to its significantly lower global warming potential compared to R-134a.

Before opening a GM AC system for service, a technician must first perform which step?

Answer: Recover all refrigerant using a certified recovery machine

EPA regulations require all refrigerant to be recovered with certified recovery equipment before opening any part of the AC system to prevent atmospheric release.

What component in a GM HVAC system is responsible for removing moisture from the refrigerant circuit?

Answer: Receiver-drier or accumulator

The receiver-drier (on TXV systems) or accumulator (on orifice tube systems) contains desiccant material that absorbs moisture from the refrigerant to prevent system damage.

On a GM dual-zone climate control system, what allows each side of the vehicle to maintain independent temperature settings?

Answer: A blend door actuator for each temperature zone

Dual-zone climate systems use separate blend door actuators for the driver and passenger sides, independently controlling air mixing to achieve different temperatures.

A customer complains their GM vehicle's AC blows cold then warm intermittently. Which component is the most likely cause?

Answer: Icing of the evaporator core due to a low refrigerant charge

A low refrigerant charge causes the evaporator to drop below freezing, forming ice that temporarily blocks airflow; as the ice melts cooling resumes, creating an intermittent symptom.

What is the purpose of the orifice tube in a GM AC system that uses this design?

Answer: Meter refrigerant flow into the evaporator by reducing pressure

The orifice tube is a fixed restriction that meters refrigerant flow into the evaporator, causing a pressure drop that allows the refrigerant to absorb heat and cool the cabin.