Mercedes Benz repair: Mercedes 95 S500 door locks, mercedes dealer, three thoughts

Question
I cannot lock or unlock any doors with the remote or with the inside lock switch. My mechanic was stumped.
Any help greatly appreciated.
Thanks.

Answer
Three thoughts come to mind.
#1. Central locking module failed.
#2. Security module failed.
#3. One lock has mechanical damage = false position signal.

This will require Mercedes dealer repair.
There is no other option with the special training and tools needed.

Have a great day.