central locking woes

[eagleman]

Dear Landy lovers
I have a 2002 defender 130 and it has developed a very frustrating issue. when I open door from inside drivers and not all the time, the central lockign kicks in, and locks all doors, very very annoying, any help appreciated , regards

[Scouse]

Did 130s have factory central locking?


You'll probably have to pop the door trim off & see what's going on. It sounds like one link is interfering with another somewhere along the line.

[POD]

Going to go on the assumption that it is factory central locking with actuators similar to Range Rovers and Discoverys of slightly earlier vintage; I spent more time than I would have liked stuffing around with the central locking on those while I had them.
The c/l actuators are not solenoids as commonly assumed, they actually have a little electric motor that drives a series of plastic gears, the last of which is a rack gear that provides linear movement to pull the lock mechanism at the same point that the door button does. The master actuator in the drivers door is the same as all the others except that it has a microswitch that is depressed by the movement of the mechanism. There is an electronic timer (contained in the master actuator on non-remote c/l) that provides power to the motors for about 1 second when this microswitch is activated.
Two things come to mind that could cause your symptoms:
The gears in the actuator are all plastic, with the exception of the little pinion gear on the motor itself. The first plastic gear very often gets some teeth stripped, which means that it won't operate the mechanism fully. One of the things that this results in is that, when it is a master actuator that has a stripped gear, the lug that pushes the little microswitch can end up parked in a position where any slight movement of the lock mechanism will cause it to press or unpress the switch.
The other is the little plastic lugs that the microswitch is mounted on may have broken off so the switch is semi-floating inside the actuator.

The actuators can be pulled apart and fiddled with. If you want to fiddle with it and save some cash, you can get a batch of non-working actuators from a wrecker or wherever, when you pull them apart you'll find that some of them will have stripped gears and some of them will have burnt-out electric motors. You can then mix and match parts to get yours working. If memory serves, they all have the mounting lugs for the microswitch, so if those are broken you can use any casing for replacement.