GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello I will help you with your question,
Does the blower motor run at all?
Can you switch the vent positions from floor to dash vents?
This is an automatic temperature control system?
OK, try a reset by removing the HVAC/ECAS fuse from the underhood fuse block. Wait 30 seconds and re install. Turn the key to the run position and wait 1 minute, turn the key off and start the engine.
Let me know if the controls come back to life