So as it’s getting pretty cold, the driver’s seat won’t heat.

Things checked:
fuse is fine
ventilation works
Power/lumbar works
all other seats heat
steering wheel heats

i can’t see any broken wires, but in all honesty I don’t know which wires I’m looking for.

Does it it sound like a new heater element, and if so is this a diy job?

 

Welcome to the forum J12345,

With a question like this, model year and specification are likely to be important details in determining the correct electrical schematic.

The cushion and squab have separate heater elements but they may be connected to a common feed. If members here have the relevant schematic, it should enable you to test for circuit continuity and heater element integrity.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Hi,

It's a 2011 X351 3.0D Portfolio with the 20 way ventilated/heated seats.

Continuity testing is a very good idea.

 

J12345, since you don't mention the passenger seat not working, this would pretty much rule out a bad fuse. So, this leaves 3 things that could potentially being bad: heating elements (there are 3 of them), the thermistor that ensures the seat does not get too hot, and the seat controller/computer.

Unfortunately, at this point, you are going to need to unbolt the seat to gain access to the wiring. Not a difficult job, but you will need to find some large torx bits to get this apart. Once you get the seat unbolted, you are going to roll it in place to be able to get at the wiring.

This is where use of a multimeter is going to come in handy. The better your multimeter, the less issues you are going to have. Before we really get into things, I want you to set your multimeter to measure resistance (looks like an upside down U with feet on it, the ohms symbol) and select the lowest scale that you can (probably 200)) and then touch the leads together. You should hopefully see the multimeter read something like 0.2 or 0.3. Whatever it reads, it should hopefully be under 1.0. Note that value as you are going to be subtracting this from future tests. Writing it down may not be a bad idea. Should probably write down all of these readings just to prevent from confusing yourself later.

Now, for the checks. If you look, you should see a connector that has a 4 pins going to it (hopefully it will say "C3HS02" either near the plug on on the plug itself). You are going to disconnect this plug and then on the side going into the seat, connect the multimeter between pins 1 (violet and green wire) and 4 (violet and gray wire). Should read between 0.99 and 1.32 ohms (remember to subtract your initial reading). If you are getting something pretty close to this, then call it good. Normally, if the seat heater fails, you will see something in the 10,000 (10K)+ range (which, if you are on the 200 scale, should make the multimeter read "OL"). If you have a good reading, continue, if you don't, your "butt" seat heater is bad. While here, you should see a violet and orange wire on pin 2 and a brown and red wire on pin 3. Change your multimeter to the 20K scale and connect the multimeter between pins 2 and 3. Do you get between 4.000K and 10.000K. If you got a good reading, then your seat temp thermometer is good. If not, you have a bad seat thermometer. Reconnect the connector and set the multimeter back to the 200 scale.

Now, you should find a connector that is going towards the back of the seat that should be a 2 pin connector. May be able to even trace the violet and gray wire between the two connectors. Disconnect this connector. Connect your multimeter on the seat side of the connector between pins 1 (violet and gray wire) and 2 (brown and blue wire). Do you get between 0.67 and 0.90 ohms? If yes, then your back heater is good. If no, the back heater is bad. Reconnect this connector.

If you checked this stuff and it all seems to be good, then odds are you have a bad seat heater module. It would be unlikely that you have a bad wire connecting things together unless you like to really move the seat a lot (ie, you and your significant other have completely different seat settings and the car needs a few seconds to readjust the seat each time you get into the car).

On a side note, if the weather is really cold outside (say, down around 0C), then you may find that the resistances may actually be out low from what I said. This should be fine. So, if the butt heater is at say 0.8, call it good. If the back heater is at 0.50, that would be good. If the thermometer is at say 3.000K, that would be good too. This is where a little bit of judgement may be needed as the values I quoted are supposed to be good between 10C and 30C.

If you need more help or don't understand what I said, let me know and I will do what I can to help you get through this.

 

Hi Thermo,

Thnaks for an excellent response. If anyone else follows this thread, to undo the seat torx you will need an E12 torx socket.

Being somewhat of an idiot, I got the multimeter out to test resistances, and can't for the life of me find the relevant plugs! All I see are connections going to the various motors.

Are they visible on the following photos?

 

how did you fix the problem ? My heated seats sometimes works, sometimes not. Mostly not ))

 

I had same issue. The peltier element was corroded. Replaced it, and Bob's your auntie.