Just bought my first Jag - what a classy car - problem is the passenger seat is stuck in the "up" position so that persons head is well above the windshield (we are tall). So....

1. the lumbar support button works. The headrest adjust is trying to work - just makes a clicking noise but does not move (like maybe a gear is stripped - but I don't care about this)
The fore and aft adjustment and the up and down adjust do not work at all. (this is the primary problem)

2. saw that the module part numbers for the two front seats were the same so I swapped them (after disconnecting the battery) this did not solve the problem.

3. Here is the really odd thing (there are three connectors on the seat module box - assuming they correspond to the three seat adjustment buttons) - when I went to plug in the seat module to the inoperative seat there were only 2 plugs available under the seat - the center plug for the module is no where to be found!

4. scratching my head on this - did someone swap out a seat from another model Jag that did not have three plugs?

Any light you could shed would be greatly appreciated - my wife does not like her head hanging out in the breeze!

 

Just double checking: is it the up down not working or the seat back tilt not working ? You were clear about fore aft being down.

You'd think that the seat movement and lumbar would be on the same fuse, but maybe someone else knows this one.

When you mentioned 2 vs 3 connections it reminded me that many more xk8s have up down on drivers side than on passenger side.

 

Both the up and down movement, and the fore and aft movement are inoperative. The seat controls for both front seats look identical - there are 3 individual adjustments switches on the side of the seat. But I just triple checked - there are only 2 plugs available on the passenger seat - while there are three on the drivers seat.

Compounding the problem - I would like to remove the seat to take a good look but it is currently in the full aft position - covering the torx bolts that I would need to remove the seat from the floor pan

I would actually be willing to manually put the seat in the lowest possible position (and just leave it there) - anyone know if this is possible if I can get the seat out of the car?

 

Sorry - I didn't totally answer your question - the tilt is also not working.

 

The passenger seat has 2 connectors because the seat does NOT have memory.

bob

 

Thanks - that clears that up. So....if the module swap did not help that would mean I have a bad connection to a motor or a bad motor? Looks like I need a wiring diagram.

Also - any words of wisdom on how to get that seat out when I can't get to those back side torx screws (seat currently in full aft position)?

 

Other people have jumped the seat motors direct from the 12v supply. Have a search on the forum. This should allow you to check if your motors are working and move the seat to get at the screws if necessary.

 

Don't start poking at wires without an Electrical Guide. Many electronic things get FRIED with the wrong input.

The seat wire harnesses get damaged from many things in that small space under the seat.

bob

 

Well, you seem to say the car is new to you, so you have none of the history of those module. These module have a design flaw whereby the circuit board rubs on the hard plastic shell and the tracks wear out. It is not entirely impossible that by now both modules are defective. They are the same, so they tend to fail the same way. As you have had these modules out already, it does not take much to open them up and have a look. The top lid has a bunch of tabs all the way around, and can snap out. Besides, replacement lids are cheap. Check the circuit board for cracks in the tracks along the edge. A magnifying glass and good lighting help. A meter did not help me much, somehow.

Separately, check the fuses. Sometimes, removing, then re-seating the fuses seem to perform some sort of reset and can make the module work for a bit.

Also, these module plugs should be kind of hard to remove and re-seat, and they click when in the proper position.

As a last ditch effort, check the part numbers in the off chance they are off of another car and in the end not compatible.

Does the seat heater work? There is also an off chance these modules are newer than the main computer recognizes, and need to be programmed in with the diagnostics software. Best I can figure, when that happens, the seat moves, but the heater does not work. Hard to know for sure.

Best of luck, keep us posted.

 

The first track to get affected by the rubbing away tracks is the seat recline forward (tilt forward) - you would hear a relay click but no motor noise.
The switches are packaged as a switch pack. You are getting power to the switch pack because lumbar works and headrest tries to (look up headrest fix on this forum). Note that these two functions do not go through the seat control module.
The connectors to the seat control module are not arranged per switch. The small connector serves the power input to the seat module, seat heaters etc. The larger connector carries the inputs from the switch pack for fore/aft, recline, etc. functions and the outputs to the corresponding motors.
If the fore/aft switch does not obviously move up and down (even though there are finger recesses that suggest that it should) you have a 3-way passenger seat rather than a 5-way and seat up/down is not supported anyway.

Are there any noises at all during recline(tilt) and fore/aft attempts?
If there are, you're probably getting power to the seat control module. If you're getting relay clicks for tilt only (especially tilt forward) look to the worn track problem. If you're getting clicks for the fore/aft attempts then the switch is probably OK so look at worn tracks, large connector/wires and motor. If no noises at all, and we assume a double motor failure is unlikely, then you may not be getting power to the module (small connector, wires, fuse) or the module's power distribution may be faulty.

Any noises?

 

If the seat module works properly on the other seat, then it is possible that the problem is in the switch. You can put a jumper wire to the correct connections on the seat switch to test it.

The headrest problem is very common and is a pretty easy fix.
See this post and specifically look at post #17. This is the part I used to repair (bought them on eBay).

 

Wow - thanks for all the suggestions - very helpful. So here is the update.

1. double checked the fuses - my american brain had me thinking fuse 1-10 would be on the left side - WRONG. So when I found a blown 20 amp fuse in spot 1 (seat module) I am thinking this could be an easy fix - WRONG AGAIN. Also checked the fuse in spot 8 (passenger seat switch pack) and that was fine.

2. so then I realized that the first time I had swapped the modules it was on a blown fuse - so I swapped modules again and bingo - I now have up and down movement and fore and aft movement. But I still have no tilt movement - I do get a clicking relay sound but no tilt motor.

3. so I have a bad passenger seat module - does anybody repair these? Also looks like a worn track issue on the tilt.

any other insights greatly appreciated - thanks again

 

...or if you are comfortable with the idea, you could try it yourself:

JagRepair.com - Jaguar Repair Information Resource

The rightmost/uppermost indicated track from the first and second photos is tilt forward - that's the one that was bad on my module. The next one over (2nd from right and 2nd uppermost) is presumably tilt backward. So look for any breaks in those two tracks.
I used an x-acto knife to scrape away the resin and make the tracks clean and bright either side of the track break so that the track would take solder. Wiping with isopropyl alcohol helps too. I used a single whisker (strand) of some old stranded AC power cord wire I had around to bridge the track break - taped it with a sliver of masking tape to hold it in place while I soldered either side to the cleaned up track (it was longer than the 1/4" inch mentioned in the article - I cut any excess off). I used a piece of electrical tape over the repair, folded underneath, for future protection instead of the epoxy recommended in the article (epoxy might be better but would be difficult to remove if you need to get to the same area again). Now, admittedly it's only been one or two weeks since the repair but the module is holding up fine.

 

I think the owner manual listing the fuse chart is confusing too because it sort of looks like it shows you the fuses the way they are set up in the box on the car, but in reality the table layout is for editing purposes. When are documentation folks going to realize that these quick charts will likely need to be consulted on the side of some unknown road, at night, in the rain, with a pissed off passenger, while trying to maintain a professional conversation with your boss on the phone (example made up)? I have now learned to use the airbag fuse to get my bearings as it is capped.

The name "Darrell Turner" frequently comes up for repairs. You can search this forum for references.

 

Thanks for the good info - I tried the module that was on the passenger side on the drivers side and it is totally dead - no tilt, no fore and aft, no up and down. My gut feel is that maybe that one is fried and beyond repair? If I find another module will I have to have it programmed to my car?

 

Is the fuse blown again?

Normally, these modules can be repaired. They seem to all fail in the same manner. The advantage of fixing them is that they can just be fitted back on the car with no issue.

New modules, if available at all, are reportedly insanely expensive through Jaguar.

Used modules are also an option. Problem is that they are all afflicted by the same design flaw, so are all worn out some. In addition, new modules may advertise themselves on the data bus with a version newer than what the main computer recognizes, and only work partially (heater not working has been reported). Having the main computer accept that module requires the "factory" software tools, typically an hour labor at a shop. You can search for VCATS for other posts with more details. So, to avoid that problem, I believe you have to make sure the replacement module is _not_newer_ than the one you have, which can be verified by the digits following the part number.

Best of luck, keep us posted.

 

Search for and download file x1002001en.pdf. That is the Jaguar XK8 Electrical guide and will show you the wire identifications and colors for the seat motors at the seat module. Careful use of a 12 vdc (ie battery charger) will confirm seat motor operation by probing the connector's motor terminals, reversing the + & gnd to obtain a reverse action.

 

try checking the tracks for a stuck penny

 

OK guys - just a heads up. I tried Darrell Turner (San Diego Soldering). Sent him the module over a month ago, he diagnosed the problems via email, sent him $100 via pay pal, and now he is not responding to email requests as to the whereabouts of my module. Should have known better........

 

Darrell has repaired many forum members modules over a couple years without complaint, mine included. He is retired Navy working out of his home so it is not like he just went out of business.

If, indeed, you cannot get this resolved please let us know as his name and contact information is widely distributed on this forum.