I am not 100% sure , which "plastic bit" you are referring to.
So you seem to have the same problems with the replacement part as before, only that before the remote new unlocked the passenger frt side and with the new part it still will not open 30% of the time, which was kind of my issue before.
Thus, what about the part, which is broken on my mechanism? It is also broken on your old part and on your new part?

 

The plastic bit I refer to is the one that is attached to the rod that is connected to the outside handle. When you move the outside handle, the rod is pushed down and the plastic bit at the end, attached to the whole latching device, opens up the latch. That plastic bit can be disconnected from the device, with the rod still seated inside the grooves of that plastic bit. You can then rotate the plastic piece to move it up or down the rod as a nut, since the rod itself has a thread on it.

Originally I was not able to lock/unlock the door with the remote. Now I can, but initially the new device refused to be opened with the door handle from outside. It works OK after some white grease on the latch.

I don't have any further information about the old latch as I haven't yet looked inside it.

Many thanks

 

That adjustment has been known to let the rod slip, thus upsetting the "rod length" and door lock operation.
Many threads discussing that issue over the years.

 

Now that I understand which plastic part you are referring to:
I thought I tackled that already in my thread, but apparently I still forgot to add the following despite my 10 PSs:
I wanted to write there already (as Mark wrote above) that this rod is known to slip in that white plastic catchment.
I figured as much when I looked at that design.
I have 2 suggestions of how to fix that design mistake:
1. Apply a little bit of black roof and gutter silicone to bond the rod to the catchment.
2. Or put a few layers of plumber's tape around the rod before snap-locking it with the white catchment.

 

Hi again.

I had a look at my old device which does not open with the remote and the plastic bit that is broken in yours looks all OK on mine. I was not able to tear apart the device and cannot see anything broken or otherwise wrong with it.

Can it be that the wiring has been damaged somewhere? The wire that goes through the side is hidden under rubber and I cannot see whether that might hide something. The contacts in the sockets where the bundles of wires from the door go to also look OK and not dirty or corroded.

Thanks

 

I went thru the trouble of removing the "rubber" which is hiding the cable. Using a heat gun allows your to remove (and then reattach) the "rubber" relatively undamaged. So there is that connector that connects to the door locking mechanism, but from there I could not find another connector of that cable in the door: That cable goes directly into the passenger compartment. The connector close to that cable about 30cm away from the locking mechanism has nothing to do with that cable - that connector is being fed by another cable and connects to the window lift motor.

I would like to think that it is possible to check, if the old mechanism is the issue or the wiring, by connecting the old mechanism to the connector on your other front door temporarily and see, if it works there. However, that would be the way to test it, if you would not have a replacement mechanism already, and if I remember correctly, you have a new (used) mechanism, where your remote works - i.e.: Didn't that proof already that your wiring is not the issue?

The issue could obviously be - as I wrote in my thread - corroded pins in the connector - that can be cleaned off (wire brush & WD40). If that is not it, maybe open the mechanism to see, if you can find/see any fault (I wrote in my thread how to open it).

 

In such problems, 95% of the time it is the microswitches. The rest is due to technical problems, such as parts breakage or so. These are the experiences from our workshop. Apparently only cars up to 2003 are affected. And just for information. WD-40 is not a lubricant. It is also not very friendly to cable insulation and plastic.

 

@Jo: I always use WD40 (or equivalent) to spray into connectors... Not good? What else shall I use to spray onto connector pins?

 

CRC Contact Cleaner or IPA (Isopropyl Alcohol) are good non residue cleaners for electronic circuit boards and switch contacts.

 

I got IPA here, but assuming that cleans the pins, it evaporates in a matter of seconds.
I do not know CRC contact cleaner, but if it just does, what it name says, it cleans, and does not protect from future oxidation...
SO I am actually looking for a way to prevent future oxidation.
Initially I would think of oil, but I figured that something like WD40 would be better...

 

Fluid film

 

Thanks, Dell,
Fluid film is a product I never heard of before. I googled it. It is available in Australia - if you really search for it - but it is pretty expensive.
But, most of all, I found several links telling me: "FLUID FILM® is non-conductive and can be applied over an established connectionto protect it from corrosion". OK, I get that, but it is not what I was looking for - I am looking for something to spray onto the pins before I close the connector - and for this specific usage, a non-conductive spray is not what I want...

 

It's non conductive to surrounding material, not if wires, plugs etc make contact. It prevents corrosion, rust, etc and is hydrophobic. It's also one of the greatest lubricants you'll ever use. It's all we used on our farm/ranch as I grew up. Rust on any farm equipment? Fluid film it. Protect vehicle undercarriage? Bug sprayer and fluid film. Gates, hinges? Fluid film it. Olden days tractors etc had exposed Cowell, fix something electic? Then fluid film it.

 

You could also try a Dielectric grease such as Permatex that you can pick up from Supercheap or any other automotive parts outlet.

I'm going to be pulling our my window wiper motor on the XJ8 shortly as it is exhibiting the random wiper park position errors associated with the conductive rotary position disc getting tainted.
Will be using the dielectric grease to maintain the disc once it has been restored to good condition.
A prig of a job to get to apparently, but the fix is relatively easy.

 

@ Dell: Yes, I read about all the versatile application for Fluid Film, incl. surrounding already MADE connections. If I find that stuff somewhere for a good price I will buy it. But as for the pins inside of a terminal:

@Mark: Yes, that sounds like it. I also saw that there are Dielectric sprays. That seems to be what I was looking for. Thanks.