I have a 2004 mazda 3 and when i want to lock the car or unlock the car with the key after i unlock it the alarm goes off. The reason why i want to use the key for the door lock is cause i get home late sometimes and dont want to wake anyone up if i use the key fob button thing then it makes the loud locking beeps. Is ur guys mazda the same when you use the key to unlock the door does the alarm go off. Another problem im having when i lock the car sometimes the rear doors dont lock or sometimes its the passenger doors that dont lock even when i press it twice or three times only sometimes at least one door doesn't lock.

 

anyone have any idea at all anything

 

Sounds like you have an aftermarket alarm that isn't working quite right. At the very least stock the car only beeps when you push the lock button twice.

Other than having the alarm checked out have you tried locking the door via the button on the door itself before you close it?