I have a 96 chevy tahoe that came with a car alarm that I can lock and unlock with a remote. When I went outside to unlock my door the remote light would flash but the doors wouldn't unlock then like 2-3 min later my alarm light in my truck stopped flashing but the doors still won't unlock. I've hit the hood of my truck to make some kind of noise but it didn't. My doors won't unlock unless I use the alarm remote. What do I have to do or what could posssibly be wrong with my truck?