1998 Dodge Stratus Door lock malfunction

1998 Dodge Stratus

I purchased this car about 5 years ago, and at that time, the power locks did not work properly. We didn't see this as a problem, and just manually locked and unlocked all the doors. There is an automatic locking function when the car gets to about 15 MPH where all the doors are locked until we unlock them. This has never been a problem. However, about 2 months ago, we started having problems with the back doors. The doors will not unlock. The only way to unlock the doors is to pull up on the lock and at the same time, try to use the power locking switch (which has never worked since we got it) until the door lock finally pops up. My concern is not so much the annoyance of having to do this, but, if we were in an accident, my children would not be able to get out of the backseat quickly. Is there a way to fix this or just turn off the auto locking function so that we can just use the locks manually?