[wingnut60]

Have you tried to activate the lock with the door open to see if the bolt is engaged and coming out? If it works with the door open, then there is a restriction in the bolt movement (alignment) not allowing the bolt to engage the striker plate when the door is closed.
If the bolt does not come out with the door open, then there is a problem in the mechanism inside the lock.
Check with the door open, that will give you an idea where the problem lies.
Joe
However, I am basing this on my own aftermarket lock--if the door has to be closed for the lock to work, my ideas don't apply.