DCRIDER

The alarm started going off on its own yesterday morning. It did it 3 more times throughout the day, and now the car wont lock or unlock. The key doesnt work on the trunk either, where the battery is. It is kinda cold, and been a few days since its been started, im pretty sure the battery is toasst now, but there is no maual key to get into the trunk. Tow it to service at mercedes, or call a locksmith and change the battery and the fuse for the horn/rf? hmmmm what do you think? didnt recieve manual key upon purchase...