Yesterday my friend wanted to open my car and when he unlocked it and opened the door, the ALARM went off. It is very loud and annoying, I had no idea how to turn it off, so I just drove off a bit, and finally my brother tried locking and unlocking the car from the passenger side door. And the alarm went off. Does this mean that I should always just open my car from the right side? I have no idea? Any ideas? My car is an 85' 300D.