lesbrea freak out HELP PLEASE

ok so i have a crazy problem and have no idea where to start that is why i registered on here for help. I have my 02 lesabre the problem started that the doors would not lock and unlock out of nowhere. now they will lock but the keypad will not unlock or it will not re lock either. then there are more problems when i start the car the dash acts like it is off, the seat belt light is on, the abs light is on, it doesnt highlight what gear i am in, has get maintenance soon light on, the radio stays off like it is in security mode, and the security light stays on, the only lights not on are the oil and check engine light. then sometimes while i am driving it will say trunk ajar and go away. but now out of nowhere this morning i was checking battery and i closed the door and now the alarm wont shut off it just keeps beeping, i disconnected the battery and reconnected the alarm still goes off i didnt even arm it. and it keeps going usually they shut off but it stops for a quick second and starts up again. So as you can see its pretty crazy mess any input would be greatly appreciated. i have checked the trunk wires to see if they were loose they are all fine, checked door wiring it is all good called dealer ship they said it might be a computer any ideas on what computer would control all this? thanks for any help!! :runaround:

The body control module controls a lot of the components that are acting up, a scanner may reveal an issue.

The DIM (Dash Integration Module, the BCM of this vehicle) is the power mode master for all of the class 2 communication modules. It would be best to get all modules scanned for loss of communication codes or any other codes. One module or a fault in the Class 2 communication circuit can mess the whole system up.