[Jeffgtx]

From his post in another thread:


+UPDATE+
Resolved by disconnecting 12v and the reconnecting! All sound is back!
Thank you to the community for help! GMC dealer didn't have a clue well at least the service writer I spoke with anyways...

 

[Jeffgtx]

Thinking about this more…. The 12v pull is likely just forcing a hard reset of the infotainment system. Has anyone discovered the method to soft reset it? You know… press a certain two buttons at the same time for 10 seconds type of thing?

 

[Jeffgtx]

According to others, pushing mute for 15 seconds.