I posted a while ago fishing for info about a faulty door lock actuator. I repaired the actuator today and I'm going to document here how I did this as it may be useful for others. A key factor (no pun intended) here is that the SV8 seems to have a function that other variants do not have, which makes the door lock actuator unique to this model. I'm not sure which function it is, I think it is the touch locking that uses the little sensor button on the door handle. This is the only XF I have owned so I don't know which variants have this and which do not; presumably the pov-pack variants have to be locked by using the fob, whereas this variant is locked with the key in one's pocket. a nice feature until you need a door lock actuator....

The fault I was experiencing is as follows; when the car was locked by whichever method, all the doors locked properly. When the car was unlocked by pressing the button on the fob, all the doors unlocked properly. When the car was unlocked by pulling the left-rear door handle, all the doors unlocked properly. When the car was unlocked by pulling on any other door handle, the left-hand rear door would not unlock. Obviously a fault in one system of a multi-system lock actuator.

i ordered a new actuator from an eBay seller in the UK offering a 'genuine part', new in box, for what seemed a reasonable sum. What turned up looked suspiciously like a non-genuine part and in fact turned out to be an imitation of apparent chicom origin and of inferior quality.

With the part on hand, I proceeded to dismantle the door, with very helpful information found in this video clip, as posted in another thread here somewhere The car being worked on in that video does not have the touch buttons on the external door handles; the harness plug for that little button was a major pain in the neck to unplug; however there is a little trick that did not become apparent until I had the lock mechanism on the bench- it would have made life easier had I known of it earlier so I will detail it here.

Removing the external handle leaves this little loom to unplug


The plug is actually mounted on a little rail contrivance, held in the normal position by a tension spring



The plug can be moved along the rails against spring pressure until it goes around the corner, where it will remain temporarily:



which puts the plug in an accessible position for disconnecting and reconnecting the little switch loom.



I wish I had been aware of this while I was dismantling the thing, it was a right cow.

The other two things I would add to the info in that video are to remove the door speaker, which gives a nice arm-sized hole that was helpful when detaching the window actuator and for retrieving dropped tools from inside the door; also I detached the window motor mechanism from the vertical rail rather than removing the rail itself; this left the window fully supported rather than dropping as it does in the video.

Once the lock mechanism was out of the door, I was able to compare it to the new part that I had purchased and confirm that not only was it an inferior chicom copy but it was a copy of a different actuator. The old is on the left, the new on the right. There is an extra bit of hardware at the top end of the old actuator that is not present on the new one. It appears i have bought the pov-pack door actuator.


Having come this far, I decided to dismantle the malfunctioning actuator and see if there was something apparent that could be fixed.
As is well documented elsewhere, there is a pop-rivet that holds the two main sections of the mechanism together, this had to be drilled out as well as removing a few screws to separate the main assemblies.


Once the assemblies are separated, a cover can be removed that reveals the extra gadgetry that is not present on the pov-pack unit. I don't know what this extra motor does, but my car has it and some other cars apparently do not. That has to be a good thing, right?


This little white lever has to be removed in order to take the cover off the actuator mechanism. I used a 5mm leather hole punch to compress the little 3-part post, whilst prying the lever upwards with a flat screwdriver.


You may note in the above photo what happened to the part number label when I gave it a wipe with my thumb to get a better look at the numbers- I nearly wiped them off. They were easier to read when dirty.

Removing the cover off the assembly reveals the internal mechanism which is a cunning contrivance of gears, racks and levers operated by two little electric motors.



I tested these two motors with a 9-volt battery and found that the larger of the two was somewhat sluggish. I may have actually found a problem! With nothing to lose, I proceeded to dismantle the new 'genuine' chinesey actuator. Along with a few other subtle differences, it can be sen that the pinion gears on the motors in the genuine actuator are both brass, whilst the pinions in the chicom unit are both plastic.


They did, however, appear similar enough to be interchangeable. I pried both motors out of the actuators- they clip in place over lugs that deliver the electrons, as opposed to the smaller motors whose terminals are soldered. Testing the two motors with the 9v battery revealed that the original spun slow and weak, whereas the new one spun with plenty of oomph.

The little spade connectors that the bigger motor sits on can be seen here with the motor removed:


I installed the new motor with the plastic gear into the original actuator and reassembled, which is mostly a reversal of disassembly but with a bit more head-scratching; I was glad to have taken lots of photos as I went. I used an M4 screw and nyloc nut instead of the pop rivet- an M5 screw would be a better fit but I didn't have an M5 nyloc nut- if preparing to do this, it would be a good idea to have on hand an M5 screw about 12mm long and nyloc.

There was a mystery spring that detached itself from the door lock assembly whilst I was wiggling it out of the door, didn't see where it came from and there was no corresponding spring on the new actuator to give me a clue. I ended up putting it here, it seemed to make sense


I reassembled the door and am pleased to report that the lock is now fully operational in all functions.

I meddled with a lot of British door lock actuators during my 20-odd years of Range Rover ownership and discovered that there were two main failure modes- sometimes the little electric motors would fail, sometimes the little plastic gears would strip. Robbing the good motors out of the ones with stripped gears, and vise-versa, one can produce a batch of good actuators from a pile of dead ones. I would expect that those little motors are the same in every door of the vehicle and probably across several models, so it may well be worth trying this if you have a faulty actuator and access to a few used ones.

 

You can buy those motors here...... https://www.ebay.co.uk/itm/2-Pieces-...r/322934208263

 

I had to replace an exterior driver's door handle and interior door reinforcement (the black plastic assembly) on my XK following an attempted theft.

Jaguar re-use design principles across model ranges and this looks similar to my XK which has "keyless entry". JLR also raid other manufacturer's parts bins because the door reinforcement and door handle are also used by Volvo.

The technique which you discovered for accessing the harness connector is known as the "harness service position" and is detailed in the Workshop Manual.

Graham

 

Well spotted. And with the metal pinion gears too.