I should also note that I'm not 100% sure it stopped working after I flashed for the first time. It might have been having this problem before I ever flashed it.
So I flashed to Carbon a while ago, everything was working perfectly, but I decided I wanted to flash back, so I used TWRP to restore my phone to its previous state. Now even with GPS on, and an application like Maps trying to use it to get a location, the GPS icon doesn't show up in the notification bar and nothing is able to get location. Furthermore, if I attempt to use headphones with my S3, I'll get a series of popping, glitchy noises, followed by audio only working out of one side. I thought this might be due to a bad solder connection in the jack itself, so I replaced the entire audio jack assembly, but the problem persists, telling me it isn't a hardware problem (with the audio jack, anyhow). Does anyone have an idea on how I could go about fixing this, or at least finding out what the issue is? I flashed back to a completely stock ROM (though I'm not sure I formatted everything entirely, I'm a little bit new to this) and I still have those two problems. Everything else works perfectly on it. I've taken good care of it, never really dropped it, nothing. Any help would be greatly appreciated. Thank you