GM GM HVAC and Climate Control

Question 1

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

Accepted Answer

R-1234yf

Answer

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

Question 2

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

Accepted Answer

Recover all refrigerant using a certified recovery machine

Answer

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

Question 3

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

Accepted Answer

Receiver-drier or accumulator

Answer

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.

Question 4

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

Accepted Answer

A blend door actuator for each temperature zone

Answer

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

Question 5

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

Accepted Answer

Icing of the evaporator core due to a low refrigerant charge

Answer

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.

(GM) General Motors Certified Practice Test

(GM) General Motors Certified Practice Test

GM GM HVAC and Climate Control