I have a 2004 xjr and when I turn on my heated seats my left tail light goes out and my reverse lights come on dim and my right rear turn signal stops working.

When my heated seats are off and I click my right turn signal the left side leds flicker.

Can anyone help me out?

 

Samm, the only thing common with all of these things is the rear electronics module and the associated plug. Granted, the wires associated with these things are separated by a few wires, so, odds are, you are looking at a bad rear electronics module. I would first access the rear electronics module (if you need to know where that is, let me know) and check the ground connections. It is possible that a bad ground for the computer is causing the issue (has multiple connections and one not working can make the computer get confused). But, after that, look at the plugs associated with the rear electronics module and make sure that they are all good (no bent pins, no water near the computer or the plug). Once you do that, you are pretty much left with the computer.

if you need any more info, let me know.

 

Ok thanks ill check it out. Where is it located at and are the heated seats connected to it?

 

Samm, the rear electronics module is located in the trunk/boot. Open the trunk/boot, look to the right and move the trunk/boot lining out of the way. You will see 2 electronic modules there (located half way between the tire and the bumper). You are after the larger of the 2 modules. It may also have a statement on it saying it is the "rear electronics module". The other module is the "Parking Brake Module".

As for the heated seats being connected to it, the rear seat heating is connected to this module, but not the front seat heaters. They are controlled by the front electronics module.

Doing a little bit more looking around, while it is conceivable, I really doubt this, you could have a problem with the CAN network (communication network between the various modules). That would be the only other thing that would be common between everything that you are seeing. Keep in mind that the rear electronics module controls all the rear lights and the rear heated seats. But, the front electronics module does the front heated seats and the front lights. Then you have this CAN network tieing the two together. Since the CAN network is sending digital signals to the different modules, unless it is somehow messing up the digital signals (normally it is an all or nothing with something like this) to only affect a limited number of things, you can rule out the CAN network.

 

There is another possibility and something that would hit my radar screen if I were diagnosing this problem and that is the luggage compartment fusebox. It contains a common circuit with the rear tail lights and front seats.

The X350 is not like the X-Type or other older technologies. Jaguar, in its infinite wisdom pushed some of the more common electrical circuitry including the associated relays into a PCB in each fuse box. These relays, along with the PCB are irreplaceable when any circuit fails and only the whole fuse box is R and R'ed. I've seen a few of them, not many, but it does happen. So, you should include that in your diagnosis.

 

ok thanks ill check that out

 

What was the cause of the problem?