I have a story from hell to share here and I hope that someone can offer me a potential solution.

I have a 2002 C320 that was making some odd sounds so I took it in to the dealer. While it was there I wanted them to look at the headlights because they are always on, even in manual mode with the switch to off. I normally wouldn't care, but went to the drive in theater a few weeks back and had to disconnect the bulbs to get them to turn off with the car running (it was raining). Anyway, I dropped my car off and the next day went to pick it up after work. The service writer told me that a couple exhaust brackets had rusted through and that I needed a new exhaust to the tune of $2200. He said they reset the computer and the lights seem to work correctly, and washed the car. They pulled it up for me and handed the key over. I tried to pop the trunk with the fob and it wouldn't work, tried locking and unlocking the door and nothing worked. The light on the fob lights, but no response from the car. I even tried holding the fob directly to the handle and nothing. I brought the key back inside and explained the issue. The guy changed my fob batteries and the problem persisted. He went inside and printed out some paperwork saying that since they reset it the car needed to relearn the key, he said it would do so after driving for 30 mins. I was annoying, but left. Soon after, I turned on the radio. Fm was very staticy on all stations and when I tried am, I got nothing, hit seek and it couldn't find any stations. I called the dealer, told them it was unacceptable that they had damaged something and they gave me a loaner car. They looked at it the next day and told me that they believe there is a short somewhere, and they want me to authorize time for them to find it. I have spoken to everyone there and their attitude is it could have happened anytime and it's not their fault. I told them there's no way I'm paying for them to blindly search for an issue. They said it is most likely in an amplifier because it keeps popping fuses. And that is an 1800 job because you have to drop the headliner. I searched online and the only solution I can find is someone in the UK had similar issues and it was resolved after replacing the alarm siren in the passenger wheel well (maybe it got water in it during the carwash?). I'm going to try this, but wanted advice on other things to try. I believe there's three amps in my car, but I don't know which one it would be. My CD changer still works, and I am willing to do this myself, but don't want to blindly replace parts. I am currently writing a stongly worded letter to the dealer owner, but I'm not holding my breath. Also as a side note, a muffler shop welded a new bracket on my exhaust for $30, so my original problem is fixed, but now I have a new issue.

Please help if you can.