I just spent 2 months hunting, finding and fixing a problem on my 2006 XK8 coupe. I want to document my findings in case it could help someone in the future. I recently purchased a 38k mile XK8 coupe. When my wife got into the passenger seat for the first time she seemed fidgety with the seat controls trying to get comfortable. When we returned home I sat in the seat and noticed the up/down position for the rear section of the seat did not work. The rest of the seat controls worked but I noticed the heated seat would not turn on as well.

With some research online this led me to believe it was the seat module. Seeing how they aren't too expensive on Ebay I got one and figured I'd start there. When it arrived, I disconnected my battery, removed the passenger seat from the vehicle and installed the new module. When I put everything back together it did not fix the problem, same issues. At this point I decide to remove the driver seat and swap the known good module over to the passenger side. Sure enough, that fixed the problem which told me the module is 100% the problem. So did I order the wrong module? Was the Ebay one I got broken?

A few things I noticed was both seat modules in my car had different part numbers and they were not original to the car since both sides had been zip tied in and you can tell they were used parts. Lastly, the working module in my car had a white sticker label on it and both the broken passenger side module and the one I ordered from ebay had a yellow sticker labels not white. After doing more research on the forums I read that these modules need to be programed and the only people can do it is a Jaguar dealer with their proprietary software.

I decided to order another back up seat module but I couldn't find any modules with the same part number I have from all three of the ones I had in hand but I ordered one with a white sticker label in hopes that could be my closest shot. I called my nearest Jaguar dealer and explained the situation and they told me they don't touch those car anymore, they are too old. The second dealer I called said yea no problem bring it in and we will re-program it, only cost an hour labor.

When the tech got to it he could not re-program the yellow sticker modules but the white sticker one worked just fine. After that the seat control came back to life and the heated seat now worked. Perfect! Was super happy to get this resolved and on my way but on the way home I went to test it out again only this time NONE of the seat controls worked and the heated seat didn't work either. I pulled into a parking lot to see if restarting the vehicle would do anything which it didn't. I had remembered when noticing that the up/down for the rear portion of the seat was not working you still could hear the power to the switch when you'd activate the control but you couldn't hear anything happening with any of the controls this time around. When I got home I got out my fuse tester and found a broken fuse in the inside driver door fuze box. Popped it out and replaced it and everything works just fine.

My guess is the tech did not disconnect the battery which I know he didn't because I would have had to re-enter the radio code to bypass the security lock when picking the vehicle up. That could have pushed a fuze to its limit when plugging in and out different seat modules and I just happen to put it over the edge. Heated seat pulling too much power? No clue but all I know is its working just great a few weeks later and seemed to be a permeant fix for now. Hope this might help someone along the way

 

Remember, the root cause of the failures of these modules is the circuit board rubbing against the hard plastic shell. The outer edge of the board eventually wears out and breaks whatever circuit track happens to be there. These outer tracks can typically be repaired by soldering a shunt wire replacing the broken edge track. Repairing the module this way typically avoids the re-programming step and is generally the preferred/cheap path forward. IOW, there is a solid chance the new-to-you modules you have are already partially worn and could use some TLC, like wrapping the edge of the board with electrical tape to prevent further damage. I would also keep the old ones around as they can normally be repaired fairly easily.

Separately, Jaguar (used to?) offers these seat control module plastic lids for ridiculously little money. Might be worth looking if that is still available and get proper replacements.

Best of luck, thanks for sharing, and keep us posted.

 

the lids are like 5 dollars

i had a car come in that fell onto the bracket and tore out like 15 caps blew up the fuse several times burned the board and it still worked perfectly after i taped it up. those things are built ford tough

 

This is why I love forums, I didn't know about that and I can see what you mean after googling it. Haven't seen this one before. I can see how the trace is super close to the edge. I can't seem to find any plastic caps though, do you have a link where I I could buy some? Thanks for taking the time to read my long post.

 

The part # is C2N3565

Your friendly neighbourhood dealership should be able to supply them:
https://parts.jaguarlandroverclassic...ule-cover.html

There's even a TSB about the issue (attached).

 

wow thank you very much.