so im not sure if this is the right place to post this but it seems right to me...

so i was sittin in the truck waiting on my gf like i usually am when i hear a dinging like the door is open but i know for a fact i shut it. so i look at the dash and it says door ajar so i open and shut the door and then it still doesnt go away so i try openin and shutting the backdoor and then try it again and its still dinging any ideas to what it is thats causing it to not recognize the door being shut?