I have a friend who has a 2000 Mazda 323 who has been experiencing some problems with his door locks.
It started out that when using the keyless entry remote one of the locks wouldn't lock. Then the problem spread and now he has three locks which won't close with the keyless entry remote.
He took it to a shop and they told him the three locks need to be replaced. However I asked him if the locks work when he uses the key, and he said all the locks work fine with the key, as in when he inserts the key in the drivers side door.
So based on this, I think the individual locks are probably fine, and there is some problem with the remote entry system.
Any ideas what the problem might be?
EDIT Nov. 23rd 2016
I spoke with my friend again, and this is the current situation:
With the remote, only the driver side passenger door locks.
When he closes the driver's door, all doors lock except the drivers side passenger door. He is simply closing the door without using the key or remote.
When he locks with the key from the driver's side the two passenger side locks lock.