A few months ago my CB stopped transmitting out of the blue. Took it to the dealer and they tore into it and was moments away from installing a new module then discovered if they turned the intercom on the CB would work. I explained that that was all good and all, but that it was just a band aid because I had never been required to turn on the intercom to use the CB. They were aware and said HD was aware too. Later that day I turned the intercom back off and have not had any issues since.
Reason all the above may be relevant? Well, I definitely think they still have a few bugs in the software related to the CB. Maybe they disabled side tone as a band aid.
So how do you turn it on and adjust side tone volume.
It won't be an off/on option. It will just be on. There isn't a way to adjust the side tone volume. It will increase/decrease with the CB audio volume setting.