Hello, I have a 2000 Ford Focus. Whenever I try to lock it either from the control or from inside the car the passenger door always has trouble locking. It either attempts to lock and fails or it locks over 3 times in a patterns of (Lock, Unlock, Lock, Unlock, Lock) and then its locked. However if I press the lock button again it does the pattern over. Now, this would not bother me but it is preventing me from arming my car. On the rare occasion that it does lock properly I will hear a beep and my car will flash its lights. How can I fix this problem so my car always arms and beeps at me?