Start with fuses maybe?

 

cell phone, and not psrt of the car

 

 

 

Ours went out on our 2009. The Nav/Climate Control etc. sits on top of the radio unit. The entire thing comes out as one unit. We had ours pulled to replace, but it started working again after they took it out and cleaned it. (Had spilled coffee on dash). A new replacement unit is in the neighborhood of $4000-$6000. A used one is a few hundred.
I didn't do it myself, but looked at the online videos as to how the unit is pulled and replaced. You need to take off the cover pieces, drop the radio unit, then remove the nav unit. A couple of plug in wiring harnesses in back. Just a few bolts holding it in accessed from the front.

I don't think its a huge job for someone who knows what they are doing - maybe one of the audio shops. But I wouldn't do it myself.