I have a ford S-Max 2012 with a child lock malfunction which keeps running the battery down. 

The Rear-Passenger Door won’t open from inside or out it is completely locked. 

The Rear-Driver Door will open from the outside but not the inside and won’t lock when locking the car.

Both car door windows won’t open either.

I’ve tried pressing the child lock button on the driver door, the light comes on but nothing happens. 

Any ideas on how to fix ?  
 

41 minutes ago, India Car12 said:

Both car door windows won’t open either.

Just need to clarify, does the car have both front and rear electric windows or does it only have front electric windows ?

16 hours ago, unofix said:

Just need to clarify, does the car have both front and rear electric windows or does it only have front electric windows ?

It has both front and rear electric windows 

Each of the front doors will most probably be fitted with Door control modules. These are the Drivers Door Module (DDM) and the Passenger Door Module (PDM). Since you have problems on both sides of the car it would seem unlikely that these we be the cause of the problem.

The Body Control Module (BCM) would be a possible cause since it controls the DDM and PDM. Before getting in to some in depth fault finding I would first recommend disconnecting the car battery for 20 to 30 minutes. Then after reconnecting it, WAIT about 5 minutes before turning on the ignition. This will cause all modules to reboot and might solve the issue.

If that fails then you are going to need FORScan and a vLinker FS cable so that you can read the Ford diagnostic trouble codes (DTC's).

On 1/17/2025 at 7:27 PM, India Car12 said:

I have a ford S-Max 2012 with a child lock malfunction which keeps running the battery down. 

The Rear-Passenger Door won’t open from inside or out it is completely locked. 

The Rear-Driver Door will open from the outside but not the inside and won’t lock when locking the car.

Both car door windows won’t open either.

I’ve tried pressing the child lock button on the driver door, the light comes on but nothing happens. 

Any ideas on how to fix ?  
 

I have the same problem ,I put key in door to disengage child lock,,now get same as you

28 minutes ago, glyndwr said:

I have the same problem

Then the suggestion will be the same as above.