Rear door not locking T5

[askg]

The rear door on my VW T5 Cali is not locking anymore. I'm not sure if it's an electrical problem (have checked all the fuses but not sure which one operates the rear door) or if it's a problem with the mecanism. The locking ring on the van is not moving anymore and it is set too far back for the lock on the door to fully catch. I opened up the locking unit fixed to the van and saw that it contained a small electric cylindrical motor. Could the problem stem from this motor not working anymore?
Any suggestions?
Many thanks