seatbelt and head light problem

[identical2none]

ok if the car is ruin the seat belts and head lights work fine they go up and down and seats belts are automatic and work but as soon as u shut the car off the loose all power and wont do anything these things are the only things that wont work when u shut the car off its has a brand new battery in it and i dont know if the raido works out not cuz it has no speakers and dosnt have a deck if someone has a idea on how to fix this please responed or my aim name is identical2none1 thank you

 

[ericismyname]

have a auto store check your alternator.

 

[identical2none]

yeah i'm going to do tat