After installing a new radio module the volume knob does not work and is stuck at the volume it is at?

Hello, there are quite a few different Radios for this vehicle, theres a base model, a Premium, Satellite Radio. And the Radio is on the CAN IHS network (CAN BUS) so yes it probably needs some kind of programming. Most modules these days do, some are plug and play, but not Radios, Is this one you installed yourself? And is it even a factory Radio or aftermarket type?

These are the wiring diagrams for the base Radio setup. You can see there are quite a few modules involved here, It looks like the Integrated Center Switch Bank Module and the Integrated Center Stack Module have Vol Sig 1 and 2, as well as Radio Sig 1 and 2, which are part of the Radio Controls. There is also a theft code that needs to be input for certain Radio models. But the Center Stack Module (screen control) and the Switch Bank look to be in control of Radio features. This is common these days, there are so many modules controlling other modules. And when one is replaced, most of the time updates need to be programmed to deal with security concerns, especially when there are Telematics Gateway modules or any type of over the air updates that modern vehicles receive without the owner even knowing about it.
Service info here is stating some type of PROXI configuration alignment with the Body Control Module is required when a Radio is replaced. I'm sure this has to be done with a scan tool that can program or configure GM modules.

I see, that's stuck pretty loud. Is this a factory radio you installed or an aftermarket type? I believe that control screen is the Integrated Center Switch or Stack module. You have controls on the steering wheel as well, correct? Service info lists a "Base" model Radio, a Premium model Radio, and a Premium 2 model Radio.

I can see options for Satellite radio and then a touch screen button for Climate Control, along with Phone and some other options I can't see, but you get the idea that there are a bunch of other modules that work along with this touch screen display, and they all communicate on a network together. Since climate controls, radio, any type of seat/comfort modules, etc, are not critical systems. So, it will be on a type of interior CANbus network that is of a slower speed (CAN-IHS 125k) than the network that controls the engine and transmission, ABS, SRS (airbag), Cluster, Steering Control module, etc. Which is on the (CAN-C 500k) network.
If you did the installation and no programming was done, I'm sure that's what the issue is. The dealership will also have software updates for modules in the vehicle. There are always updates. But below are the OEM wiring diagrams for that CAN IHS network, if this is the Premium 2 Radio setup, the Volume control is done by the Integrated Center Stack Switch Bank module and the Integrated Center Stack module. (Diagrams 3, 4) and that info is transmitted over the network to the Radio.

Here are some examples of Technical Service Bulletins on just the Radio software, (TSB 1 diagrams 1, 2) (TSB 2 diagram 3) (TSB 3 diagram 4). And there is also a Recall on the Transmission Control Module- diagram 5.