Replacing control unit for rear-differential lock

Information 

No values (data) are read or written when replacing the rear-differential lock control unit.

1. Replace control unit. → 397719 REMOVING AND INSTALLING SERVO MOTOR FOR REAR-DIFFERENTIAL LOCK 
2. Switch on the ignition.
3. Start the vehicle and leave it running at idle speed for approx. 30 seconds.
4. Perform a test drive and check the function of the rear-differential lock.