When the car is running, the AC is on full blast at 70 degrees, but I am unable to turn it off or change the temperature. None of the buttons on the head unit work, so I cannot control and turn on the radio either. What is the best fix/repair for this? And how much money will it be?

 

What year is your car? Odds are that control unit is hosed, since it's integrated. You'll probably need a new radio or aftermarket radio with JDM or Metra kit.

 

2003 sedan without bose. If I got this it would also fix the AC problem?

 

common problem on the 2003's.

The AC/radio board took a dump. You'll need to replace it, or go aftermarket. Neither is cheap

 

It should, but the Metra kit is pretty ugly in my opinion. I'd first double check fuses and make sure the obvious has been covered first. JDM kit is 350-400 dollars and the Metra is about 200 bucks or you can try finding a used head unit to keep it stock.

 

I bought an entire used Bose head unit with NAV for $350 on ebay when my cd changer and nav broke. For a non-Bose w/o Nav, you should be able to get one for way less than that and swap it out. Try that route first and see if it fixes the issue.

I dislike the Metra kit also, which is why I didn't upgrade to a DD system. and the JDM kit is quite pricey just for the cover.