I found the problem with the central locking system.

When the truck rear-ended us the trunk took all the force and the "Trunk Lid Lock Actuator" cracked, and the air would leak during locking. The body shop did not notice the crack and reinstalled the same part. They must not have tested the locking system before I picked up the car.

I have plugged that hose until I can locate the new actuator, so now I can lock the doors again. AND the trunk can still be locked and unlocked with the key, so my mystery is solved.
It was an uneasy feeling not being able to lock the 420 in a public area. We retired from Atlanta GA and there you always locked your vehicle. The seats would not be there if the doors were unlocked.

Thanks again!!