It appears that it is not your lock giving you a problem but either the operating rods and levers or the central locking actuator.
Land rover discovery right side door locks dont work.
Around 300 and a couple of hours to fit it yourself if you are that way inclined.
So the voice of experience says it needs a new door lock actuator.
Malfunctioning power door lock actuator.
One of the common problems with the land rover discovery 1 is the spring in the door locks can fail preventing you from opening without the key.
The only way to open them is reach over and pull the latch.
So the land rover mechnic says all three doors locks need to be replaced.
The power door lock actuator is the part of the power door lock system that actually controls the locks.
A 1999 2002 part fits all years 1999 2000 2001 and 2002.
You will have to take the door card off and check that these two area s are operating correctly first.
Seems odd to me that all three doors have to be fixed.
This is how to fix the door locks that would click when you lock with a remote but wont lock the door there was no repair info on the internet so i decided.
320 00 per door plus labor.
It is certainly easier removing the window regulator from the glass with two pairs of hands though.
Discovery door lock actuators parts are listed by their year.
With the door skin off you ll need to look at the pivots and rods that connect the remote locking to the lock pull and from there to the lock mechanism inside the door and the lock on the outside.
If it feels that it gets stuck than i would say its your drivers actuator.
Do your drivers side lock go down.
If it goes up and down with the key with no problem and the other door locks dont react then the last owners disconnected the switch.
The actuator is a series of gears with a set of rack and pinion gears at the end.
When the actuator gets the signal from the power door lock switch a small motor turns the gears.
If the pivot points aren t cracked then often you can adjust the pull rods so that the lock disengages lower in the pull this should fix the problem.
So now it will only be a manual.