Steering wheel controls stopped working?

In the last few days all four of the top buttons on my steering wheel that control my factory radio have stopped working. The radio still works fine if I reach over and turn the knobs, the bottom four buttons that control the DIC still work, I don’t have an airbag light, so I know it’s not the clock spring. Is there something else that powers those four buttons, a fuse I’m missing, a wire that broke, something? Yes, I know I can reach over and do it manually, but it’s nice to be able to hit the mute button with my thumb when I get a call being that I use the truck for work I’m in it all the time.