Thought I'd post a few pics how to get to door locks and switches.
Two days ago, I got to the car, opened the rear door and was no longer able to close them, door lock was simply not engaging on the right rear doors, plus relay was clicking with the doors open since I've bought the car in 2019 so I've finally decided to tackle it.
Doors on an X300 are generally pain to work on unless you have tiny hands. So first off all, one of these trim removal screwdrivers is required to pull all the push fit clips that hold the door card to the door. Its possible to do it without it but if you want to have any chance of removing door card without snapping most clips you should really invest in one. They are super cheap too.



Then you ought to buy the clips themselves as most likely a couple will break whatever you try, they are just old and brittle. This is what you need to get:


They are widely available and cheap from the usual websites.
I'm not going to go into too much detail on removing door card itself, its pretty much self explanatory, door handle enclosure comes off first, then wood, then top, then arm rest and you pull the whole thing off and you end up with this:



Slowly peel the right side of the black cover only, its not necessary to remove the whole thing. The window of course needs to be all the way up.
Behind it you'll see this:



Screw is already removed here but it will have to come out to get a bit of extra space to get to the lock and actuator.

Now familiarize yourself with how the lock sits in the door and how all the linkages are attached to it.

Remove the top plunger thingy. Its secured with a plastic bit but very easy to remove.

Then remove two 7mm bolts holding up door handle, you'll need a small spanner to do the right bolt as not enough space for most sockets. Make sure you have a magnet in case bolt drops down.

Remove door handle.

This is also perfect time to replace door handle seals. Old ones are definitely shot and not doing what they suppose to do, even if looking ok from outside. They are ~$20 for a pair.

Remove this plug/socket(it sits in the way):




With the door handle off, remove 3 torx screws holding the door lock, move the window channel slightly forward and slide the door lock and actuator down(there is just enough space to force it down at this point)



Only at this point, you will have good access to the inner door handle cable, remove little metal retainer first and then pull the cable off and now you can remove the whole thing out of the door.


At this point you'll realise that the switch can be replaced in situ without removing the whole lock but only if you've removed it a number of times in the past so dont beat yourself over it

Here's the switch:


You ought to have a replacement ready, cut the wires off and solder new thing on, again they are widely available from usual websites

That said, if you dont have a replacement for your stick door switch, you can cut the little rubber tip and spray contact cleaner inside and work the switch on and off until it starts to work ok, bit crude but works.

Clean your lock and then spray/oil/grease the lock as much as you can and this will bring it back to like new condition. Despite how the door might open from the outside you'll be surprised how much improvement a bit of spray/grease makes.

Reassembly is a reversal of the disassembly.

Oh and of course my lock was ok but completely random piece of plastic was pulled out of it, that was preventing me from locking the doors. Really no idea how it got there in the first place!




It only showed up after I've worked the latch a number of times manually and then I was able to pull it out

Anyway, hope this helps someone!

Oh and this is 2-3 hours of work, at least on first doors.