C28 96' driver side door lock?
 

When using the key it will not lock all the doors, only the drivers side. Keyless entry went bad some time ago. Auto I was told that one side of the lock may have an air leak. When you lock the trunk all doors will lock but you are unable to start the auto with the key untill you manually open the trunck. The problem is my daughter -college student- can not lock her car from the drivers side because of this problem. Can someone tell me a fix? Once I get this fixed I am going to install an aftermarket keyless entry to open, lock start for her. This is her Xmas present.

Thanks in advance....