The seats heater in my recently purchased 2005 XK8 presents a problem. When the passenger seat heater is turned on, both seats heat. When the driver's seat heater switch is turned on nothing happens to either seat. I suspect a previous owner of the car may have botched a repair. Suggestions as to what to do greatly appreciated.

 

Certainly sounds like a botched repair. The way you describe it, connections for both heaters may have been paired to the passenger switch if the driver's switch had failed. You are going to have to remove the switchpack to find out.

Graham

 

The root cause of this is typically the seat control modules. They are attached on the underside of each seat, towards the front and held by 2 screws. They can easily be removed and opened up. The problem is that the circuit board inside the module is resting on hard plastic and eventually the electrical tracks on the outer edge wear out and the circuit dies. One of the symptoms is the failed heater. Sometimes some of the seat controls fail, too. The diagnostics involves swapping driver side and passenger side modules to see if the problem moves with the module. Once identified, modules can be repaired, typically by soldering shunt wires as replacement for the broken tracks. Some forum members also offer a repair service for a fee. This is the "standard" understanding. In your case, it is possible someone did not have all the details and ended up hacking the wiring somehow. If you suspect a hack repair, try and find some clues. Check the wiring under the seats. It is also possible there is some hacking behind the button panel. Unfortunately, the center arm rest/console has to come out for this, but it is not a terribly hard job to do.

PS: the full electrical diagram is available on jagrepair.com. Check the manual for the 2003 model (X103).

 

fmertz, Thanks again for the reply. Do you know of any reputable Jaguar repair shops in the Eastern PA area that would know how to repair the seat heater issue?

 

PA's got a huge eastern border:-). I sent you a PM in case you are nearby.

John

 

I would like to add to this. Your 2005 has a different control module than all previous versions. Typically someone sends in their unit for repair and accepts a repaired unit in exchange (plus payment). All functions will work except for the seat heater and sometimes the folding mirrors (if programmed) will go crazy. Make certain you have the correct part number first.

wj

 

I have had this exact same problem more than once.

In both occurrences for me it was just a poor connection at the plug under the driver seat.

I think both times the problem was after I had the seat out for other maintenance and I failed to get the harness secured, allowing the plug(s) to get compromised from excess pulling/tension. On my 2004 there is a plastic mount that slides onto a metal pin on the seat frame to keep the harness out of harms way. Even if you have not had the seat out like me, I could see a case where somebody pushed something under the seat and dislodged that plastic mount from its pin and ultimately caused the harness to get pulled enough to affect the seat heater.

I would start there with the connections. You will probably have to remove the 4 bolts holding the seat in place to re-seat the connectors.

So far the issues in earlier model years with seat controllers don't seem to be present in 2004 and up.

 

not quite so, I communicated with 5~6 with 2005-6, they had the front trace get worn away and some had theirs fixed and others swapped out only to be unpleasantly surprised with the heater/mirror issues (using the incorrect part number which btw looks identical).
Hopefully yours is simply a loose connection or a worn trace, good luck.
wj