Need a factory stereo wiring diagram non-Bose system?

Sure, here are the stereo wiring diagrams and a guide to help you test the connections.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know if you need anything else to get the problem fixed.

Could you tell me what these wires represent? Thank you again. 2011 GMC Sierra 1500 sl 4.8 lt flex fuel they are from back of radio.

These are out of the back of the radio, correct? You can use the wiring diagrams to see where each wire goes and what it does.