I just bought a Mazda 3 2015 and it has some problems, the control knob doesn't allow me to select anything when pushing the control, the seller told me that it stopped working when he changed the battery. Anyone knows how to fix it?
I'd also take a look for anything spilld in it. It should be obvious as it can be hard to clean between the buttons.
The good news here is that its pretty easy to fix. I spilled a bit of tea into mine...on multiple occasions. Pulled it apart and cleaned it out. Works like new.
Two recommendations: you can use a silicon lubricant on it safely. I've been using it for over a year now. Second, get some plastic trim tools. Not expensive and will prevent you damaging the interior trim trying to pull it apart with a screwdriver.