I have my seat detached, but it doesn't look like my seat has a connector for the harness. If you look at the picture it looks like it's been screwed in place. The other end goes into the floor.

 

You have to remove the plate just in front of the seat that has carpet glued to it. Remove the forward carpet, and you will find two screws under a carpet flap holding the cover plate down. Then you can remove the plate, and the connectors for the seat harness. There is more than one.

 

Tomorrow, I will see if I can just cut that screw that is sticking up and turn the clamp to the other side. The connector is just behind it. Then I will remove the clamp and use a tie wrap to secure it back to the frame. That way if I ever need to remove the seat again, it will be easy. I looked at pulling the rug up, but it is glued down and I would have to rip it up in order to get to the plate. The motor stopped working when I tried to move it back the last time, so I suspect it is jammed. No matter, they both go on my bench in the morning. It will be good time to give them both a good cleaning and go through both motors if possible.

 

As usual, the answer is in the workshop manual. Vol 3 Section 76.70.20

Unless you're completely dismantling all the wiring from the seat, you don't remove that clamp to disconnect the seat wiring from the car. you disconnect it from the seat ecu.

As mentioned, I think there's 3 connections. See the attached pics which show the seat ecu (under the carpet) before and after I disconnected it. That seems to imply there's one multi-wire beige plug to be disconnected, one black to green plug, and I think there's one other somewhere. The workshop manual explains it.

Good luck

Paul

 

Ok, The plastic clamp if off and now out of the way. The harness is now disconnected. The rails are off the seat. I found two loose bolts jammed in the rails and they are now out. When the seat was in the car, the seat would only move a couple of inches then stop. Probably the loose bolts, but I want to make sure and test the motor before I put it all back together and in the car. If I also have a problem with the motors, I want to deal with that next.

 

Everything is now lubricated, loose bolts are gone and the motor is working fine. So, now I just need to mount the frame to the seat, put it in the car and hook it up. I didn't get a chance to test the seat heater so I will do that later. So, now I can adjust my seat and make it fit me.

 

Before bolting the seat to the floor test it. I bet the seat still moves an inch, then stops. In that case the problem is in the potentiometer that monitors the movement of the seat and sends it to seat memory module.

 

So far, the seat is working fine.

 

So I managed to fix my XJS seat memory and also the strange movement of the seat to forward and back (when you press the button the seat moved only inch, then you had to press the button again and the cycle repeated). As I have also fixed this issue with my XJR6 I suspected that the issue is the same - the faulty potentiometer. Here is detailed information how to fix seat memory on X300 model: https://www.jaguarforums.com/forum/x...meters-131192/

XJS seats are a bit different and here is how I fixed mine. First get this seat out from the car. You need to release 2 bolts in the front and 2 bolts at the back of seat rail. Very annoying to do if your seat moves only inch by inch.... When it is out of the car then separate the bottom part from the seat. Again there are 4 bolts and they are a bit tricky to get off (and even tricky to get back afterwards... Do not rest until you have this part on your table

The cause of all the trouble in the world is this small device on the front right corner of the seat frame (upper left corner in the picture above). Now I used small motorcycle battery to move the seat position approx. to the middle position. This is necessary to help you to position the potentiometer to the right position when you put everything back together afterwards. I cant remember which color of the wires needed to be connected unfortunately, but it can be traced from electric scheme.

Unscrew it and bend it carefully out of the position:





Now comes the tricky part. You have to carefully to pry this potentiometer into 2 parts.


Now you see the troublemaker, the part that is connected with wires. Pull it carefully out and you will discover the design flaw of this part. It has connecting shaft inside and the little "arms" of the shaft are broken. The plastic will not tolerate the stress of the tensioner metal ring and eventually it brakes. After that it cant turn when seat is moving and potentiometer electric value is not changing. The seat memory control unit detects that something is not wright and is not allowing the movement and seat memory to work because of that. The result is inch by inch movement of the seat and no working seat memory.


So how to fix it? There are some other solutions also (look at the link I used in the beginning of my post) but as my device had 4 "arms" still attached to the shaft, it was rather easy to do. I tried several options and this one gave the best results. I used the heat shrinking cover of the wire connectors that had perfect inner diameter. I cut out small tubular part and put it over the joint. The plastic connects the joint to the ball so it is firm enough but still possible to turn when overloaded. After some try and error it was perfect grip.





Now use voltmeter to test if the potentiometer gives out different reading when you turn it. IF NOT, then your hand built connection is too weak and the device is not it is not working properly yet. Open it again and try to make connection that is more firm. Repeat the check. If everything works, before putting everything back together, first turn the potentiometer to the position where it is approx. in the middle position. It does not have to 100% in the middle but close enough, Thats why I noted before that you should slide the seat to the middle position before you start. Now your seat is in the middle and also potentiometer is in suitable matching position.

Put it carefully back together. When I put back the seat and tried it first time it didn't move at all. WTF??? It turned out that seat was not firmly grounded, after attaching it to the ground and checking all wiring, everything started to work perfectly. I opened beer, slided myself in all possible directions, noticed that also the mirror memory function is now working. Job well done

Oh and also I managed to repair the lumbar support. Before the pump engine was making noise but nothing happened in the lumbar area so I was suspecting a leak somewhere. When I opened the seat the problem was easy to find:



The old connection tube was made of some bad material that has been soft when it was made but today it is hardened and it has broken off. So I replaced it with 5mm rubber tube. I also opened up the grey pocket that holds the pump. It has inside layer made of foam. I think it is for sound insulation? Unfortunately the foam has turned into powder today. It will fly out every time when you lean to the back and spray this dirt to your interior. It also stinks... So I removed it, replaced it with new foam and sewed it back together.

Now I get some nice action in lumbar area

And while the seat was off, the upholstery guy also repaired the bottom of the seat. The side support of the seat bottom has worn off as they all eventually will, so he replaced the foam and made the support nice and firm. Checked the seat heating wiring also, everything OK.