GMC Troubleshooting Questions? Ask a Mechanic for Answers
Ok, first, quite a bit of information is missing -
Model of your GMC?
Which vents is it blowing out of only - dash, defrost, floor?
Automatic or manual climate controls?
Are you wanting to attempt to repair yourself, which will void the warranty since it is a 2016, or are you just wanting to know what to tell the dealership is the likely issue?
Please note that continued poor accept rate now leads to experts ignoring future questions you may post as they realize that they will not be paid for their time or services. Thank you
Again which vents - the front dash vents, the floor vents, or the defroster vents?