Fault-tracing information

Condition 

Fig 1: Identifying Childlock Switch

Courtesy of VOLVO CARS OF NORTH AMERICA.

• Diagnostic trouble codes (DTCs) missing.
• One or both of the rear doors locks/does not lock to/from the child safe position.

Possible Source 

• Open-circuit in the wiring to the child lock motors.
• Fault in the child lock motors.