FastMustang06

My passenger door lock just quit working right!Once you start running the car, the door should automatically lock in both driver and passenger doors. But mine wont lock at all unless you have to manually push the pin down and unlock it using the door handle.
I have the Python remote start / alarm system and even using the remote control will only unlock the driver's side but not the passenger side. I do hear the motor trying to work but the door lock just won't come up! My installer told me it's a mechanical problem and it should be covered by warranty.
Does anyone have this kind of problem too? How did you fix it?