Rover's Vikingship   The Central Door Locking System    Rover's Vikingship


This part of site is an attempt to organize and add to the web resources for the Rover SD1 to form a cohesive and easily usable guide for those of us without easy access to expert repair and/or advice. It is not offered in any way as a definitive source and we take no responsibility for any errors that may exist.

Central Door Locking System

Another feather of the 3500 is the central door locking system. It comprises three control switches (1) an integral lock and unlock solenoid in the tail gate and each side door (2) and the control unit (3).

The circuit is powered through an inline fuse located in the right-hand foot well.
All five locks can be operated simultaneously by turning the key in either frontdoor.
From inside the car the switch, mounted on the drivers armrest, will operate the locks.
The tail gate can also be opened by key in the conventional way.
The lock can be isolated from the central system by turning the key fully clockwise before removal. In the event of an electrical failure the front-doors and tail gate can be locked or unlocked by key. And from inside the car by using the door mounted rocker switches.

This is the electrical circuit you will find it easier to understand as two identical relay control circuits, one to lock the doors the other to unlock the doors.

The circuit is protected by an inline fuse. From the fuse on the right, current (red) flows through the two resisters and charges the capacitors.
A selection made at any control switch will cause both capacitors to discharge through the appropriate relay coil. This momentarily closes the relay contacts and battery voltages supplied to the appropriate windings of the solenoids thereby locking or unlocking the doors as selected.
Approximately five seconds after the control switch is been released, the capacitors (blue) are recharged.

Another selection can then be made. Again by adopting a methodological approach to troubleshooting, time and effort will be saved. First establish which parts of the system are inoperative. If the failure is total, check the state of the battery, the line fuse, all leads and connections and finally the capacitors. If all doors fail to lock or fail to unlock suspect the appropriate relay and it's control circuit.
It is unlikely that all five solenoids would fail simultaneously.
If one control switch fails to operate the fault is in the switch or it's connecting lead.
If one solenoid fails to operate check it's supply leads and earth connection. Then look for an mechanical failure before replacing it. That completes the section on the electric door locking system.

Special thanks to Drs. L. de Boer.



© rwp aug. 2004