New Member With Faulty Rear Door Lock Question

[Gary2604]

My recently acquired 2012 Galaxy has rear passenger side door lock issue. There are many discussions on here relating to bad wiring etc but I don't see any that specifically addresses my issue but apologies if this has been covered elsewhere.

When I got the car the 'child lock malfunction' message was being displayed. The only mechanical fault was that you could not open the passenger side rear door from within the car. The power locks worked from the key as did the window from both the door and drivers door switches. I discovered the manual child lock switch on the door. Turning that has the door now opening from inside but the internal (drivers door) switch has no effect on the door. When activated you can here the rear drivers door lock click but nothing from the passenger side, it does prevent the window being lowered but does not activate the child door lock. As stated the main door lock works perfectly with the remote key.

So my question is, does the door lock have two separate motors, one for central remote locking and one for the child lock function? If so my conclusion is that is more likely that lock has failed rather than broken door wiring given everything else works?

I should add that both the passenger and rear passenger doors are not original to the car due to accident damage. Using Forscan I see a message stating that passenger side door module is not compatible......but passenger door works perfectly. Also from Forscan I only see drivers and passengers side module.....no rear door modules....do the front modules control the rear modules? If so maybe that's the real issue and I need to replace a module? But why then does the central locking work........questions....questions