Hello, this is my first time posting on here. I have a 2005 Mazda 6 T2. Today when locking the car I noticed the flashing alarm light wasn't flashing and thought one of the doors might not be closed properly, on checking the doors I found that the passenger door wasn't locking, all other doors were locked. I unlocked the car and tried again with the same result. I unlocked the car again, sat in the driversseat and locked the passenger door by reaching across and locking it manually from inside the car. I then got out and checked from the outside that the door was locked and it was. I then pressed the remote lock button and all the car was locked, however when I pressed to unlock the car, all the car unlocked apart from the passenger door which was still locked. The passenger door will lock and unlock manually from inside the car but the remote will not operate the passenger door lock. I was wondering if anybody had any ideas about what the fault could be and if anyone could offer any help and advise. Thank you

 

It sounds like you need to replace the passenger door lock actuator. Its an electric motor for the locks.

 

Sometimes all it needs is a bit of lubrication. Still you need to take off the door panel.