First find out if the door lock actuator works in any mode i e.
How to make a door lock not work.
The lock mechanism may not work simply because the lock is dirty or dry and needs to be lubricated with graphite do not use any type of oil because this will gum up the works.
Symptoms of a failing door lock actuator.
Door lock actuators are.
How to fix a door that will not lock.
If the door lock actuators fail they will disable the power door lock feature from working.
An improperly functioning latch may be the result of a poorly fitting door.
Also a broken bolt or latch that causes your door lock to jam might be a symptom of a much larger issue like an attempted home break in.
Does it work with the door switches but not the remote key fob.
This will require the driver to use the key to lock or unlock the doors and can disable the power door locks completely for vehicles that do not use a traditional key such as newer luxury vehicles.
For serious lock problems it is usually best to call a locksmith or to replace the lock.
The wd 40 lubricant will work for a short time to lubricate but will eventually gum up the pin tumblers and cause them to stick in the chamber therefore making it difficult to unlock the door.
It is not recommended to use wd 40 in or on any type of door locks or deadbolts.
Door locking problems almost always originate in the door latch not the locking mechanism.