Possible MFD failure or 12v battery failure?

Hi everyone! I hope you’re doing well today. I have a 2005 Gen 2 Prius with about 157,000 miles, and I recently ran into an issue and I’m not sure what it could be. Based on my research, it seems it’s either a failing MFD or failing 12v battery. A couple of days ago, I noticed that the controls on my radio aren’t working. The buttons don’t beep and I cannot adjust the volume. The steering wheel volume buttons don’t work either. When I select audio, the dreaded “Audio Off” is displayed on the screen. I tried things that were suggested on PriusChat (gently smack radio, test steering wheel buttons), but nothing is helping and the radio buttons just won’t work. However, my phone connects to Bluetooth. The display looks fine, and air conditioner control still works, so I can’t tell if this is an issue with the MFD or just the radio? I do have a couple of questions, but please bear in mind I’m not great with cars or very DIY-savvy. To the best of your ability, it would help if your answers are in laymens terms or ELI5 (if you’re familiar with that).

1) Does this sound like an MFD, 12v battery, or simply just radio issue to you, given that the rest of the display still works (especially the air conditioning controls)

2) I’ve heard MFD repairs are pricey. Again, I don’t know a ton about cars but from my research on PriusChat, it seems like people advise buying a second-hand MFD. If you do go that route, can you buy the MFD secondhand and then have the dealer install it? Or are you basically on your own if you buy a used MFD? Sorry if that’s a dumb question, but yeah, not the most car-savvy.

2) I’m also not in the greatest place financially right now, so if it is a failing MFD, is it possible to live without the MFD for sometime? I just wasn’t sure if a dead MFD means the car doesn’t drive either or if one can live without the MFD? From my research, it seems that the radio/air conditioning are the big two MFD related things. It wouldn’t be comfortable, but if the car is still drivable without the MFD, then could one just put off an MFD repair for some time?

Thanks everyone!

 

Update from OP: Yesterday, I got in the car and my car connected to Bluetooth and the radio worked as normal. But this morning we are back to square one, it’s not working again.