This is a cheap and easy fix.
One door doesnt lock cr.
Defrost the lock to check an individual lock mechanism work the door lock manually up and down or backwards and forwards in newer vehicles while using the auto lock button at the same time.
Operate each door lock switch in the vehicle to determine if the doors can be locked with any of the switches.
If one door doesn t work but others do the problem could be a blown fuse.
Just make sure the key is on.
Another symptom of a potential problem with the power door lock actuators are door locks that behave erratically.
If the lock tries to move then the problem could be a frozen lock mechanism or a faulty solenoid.
Replacing it may require removing the car door panel.
If the doors lock with any one switch the most likely problem is a defective switch on the door that is inoperative.
If the remote key won t unlock car door even after battery swapping or fixing the battery contacts try a distant unlocking service.
Again if one door doesn t work but others do the problem could be with the door lock solenoid.
A fuse is blown.
Most car brands offer a remote door unlock service for emergencies such as a broken smart fob and locking the keys inside the car.
Power door locks behave erratically.
You will need to set these services up ahead of time.
If the actuators have any sort of internal or wiring issue it may cause them to rapidly lock and unlock unexpectedly or cause them to function intermittently.