Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
HVAC Control Module
The HVAC control module is a GMLAN device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). The control module supports the following features:
| Feature | Availability |
|---|---|
| Afterblow | Available if reprogrammed by the technician |
| Purge | Yes |
| Personalization | Yes |
| Actuator Calibration | No |
| Heated Seat Control | Optional |
The HVAC control module will receive information that defines the current driver of the vehicle from the driver door module (DDM) through GMLAN communication. The HVAC system will memorize the following system configurations for up to 2 unique drivers:
- Driver set temperature
- Passenger set temperature
- Mode
- Blower motor speed
- A/C compressor request, auto ON or A/C OFF
This information shall be stored inside the HVAC control module memory. When a different driver identification button is selected the HVAC control module will recall the appropriate driver settings. When the HVAC control module is first turned on, the last stored settings for the current driver will be activated except for the rear defrost and heated seat settings.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.