Well, my wife who has hijacked my 2001 coupe and drives it daily, reported to me today that she didn't think the heater was working and also the heated seat wouldn't turn on.

I took it for a drive and found that although the climate control appears to be functioning completely normally, there is indeed no heat coming from it, no matter what setting it is on.

I then looked at the heated seat switch and found that not only does the switch not light up, none of the switches in that row operate either, so two seat heaters, traction control, front and rear fog lights etc. The switch back lighting is functioning. Everything above and below this row of switches is functioning correctly.

Ideas gratefully received please, as if I don't sort this out quickly my wife is likely to give me a considerable amount of grief
Many thanks,

Andy

 

Try this Andy, tilt the drivers seat up as far as it will go. Disconnect the the module that you will see at the front. Wait 10 minutes and reconnect then try again.

 

Thanks for that Jim. Is that the drivers seat module and if so, what part does that play in heat generation from the climate control etc?
Andy

 

The more likely answer is that the heater water pump is not pumping any water to the core any more. Check the fuse. It could also be worn. There are many write-ups about this, including how to repair it (new brushes). Apparently a pain to replace, though.

Separately, there is an off chance the control system is confused. Check the display when you ask for external temp. If the number has no relation to the actual outside temp, then that sensor needs to be checked.

Have you performed basic debugging? Tried with recirc? Push the heat on max (HI)? Put the vent to face only? Check of the coolant level? Confirmed the fans are running?

In addition, there is a great built-in procedure for diagnostic of the climate control. You might want to start there if there are any codes.

The seat heater is part of the seat control module. If the seat can still be moved, then the module needs to be repaired. There are lots of posts about this, the repair involves fixing broken tracks on the edge of the control board. If the seat does not move, then check the fuses (1 per side, located in the "fascia" when you open the doors).

Best of luck, keep us posted.

 

Thanks for that. I understand where you're coming from, but my main concern is that both these issues happened at the same time and it's not just the drivers side seat heater not working, nothing in that row of switches is working, i.e. fog lights front and rear, passenger seat heater and traction control.
I'm not big on coincidence, so I suspect there is a link between the lack of heat and the switches not working.
I did try all the settings on the climate control including max heat - HI- at face level, recirc and max cooling -LO-, but the link to the climate control errors is most helpful and I'll try that tomorrow and see what is says.
Thanks again
Andy

 

The reason I say that Andy is when I bought my XK8 that bank of switches did not work. By disconnecting the drivers seat module and then reconnecting, it all came good.

It's worth trying first as it won't cost you a penny.

 

Thanks Jim, I'm happy to try anything, especially if it's worked for someone else already.
I'll let you know how I get on.

Andy

 

Take a look at fig 12.1 – 12.4. The seat heaters are controlled by the seat control module.

Link http://jagrepair.com/images/AutoRepa.../jagxk2001.pdf

As for the no heat you need to check the fuse for the heater pump. Is located in the engine compartment left side I think #15 10a.

Now the bulbs in the back of the control panel lighting it are switched with the car lights but the light indicating what you selected I believe comes from the module.

 

OK, so I've established that fuse no. 3 in the Engine Compartment Fuse Box - Left Hand Side, i,e, just behind the ABS pump has blown and replacement fuses blow as soon as the ignition is turned on.

This fuse is 5A and is listed as 'Security sounder, headlamp levelling motors, headlamp levelling switch, ignition +ve, centre console switch pack, adaptive cruise control.'

My obvious interest is in the 'centre console switch pack' part of it. I haven't had time yet, but I'll start going through the wiring diagrams to try and figure where the short or high current is coming from.

Any ideas, as always, gratefully received.
Andy

 

Another bit of info I forgot to put in the last post, is that if I operate either heated seat switch, I can hear a relay latching under the relevant seat (presumably a micro relay in the control module), so something is working but the seat heater is not switching on.

Also, I have run a diagnostic on the climate control and it showed a code no. 14, which is listed as 'Water temperature input malfunction. Instrument cluster output. Refer PDU.
Not knowing if this is historic or not, I cleared the code and re started the engine a couple of times and it didn't re appear.
Andy

 

The most likely culprit for fuse #3 is the security sounder, located behind the RHS headlamp somewhere. The internal NiCd batteries corrode and it starts to digest itself.

https://www.jaguarforums.com/forum/x...0/#post1543965

You can safely just unplug it.

HTH,
Mike

 

If the security sounder batteries go bad, is there any indication when locking or unlocking the doors ? Has anybody ever replaced the batteries in one ? I'm curious because I've never heard of this before, and my car is 10 years old. I'm just wondering if this can be done proactively to avoid the carnage.

 

If the chirp sounder is at fault the easiest thing to do is disconnect it and tape up the wiring to it.

 

You might want to do some research. There were some posts recently, and it became apparent that only some sounders came with built-in batteries. I was left with the impression that US cars did not have this extra battery, with car theft possibly being less of a concern here. It boils down to whatever part number you have in your particular car I suppose. For all we know, that battery supplies voltage to the radio when the main battery is being replaced, avoiding the tripping of the anti-theft codes, all non-US features, typically.

Best of luck, keep us posted.

 

The security sounder has never chirped since I had the car, about 4 years ago and I have heard about the batteries going bad and as you say, the process of self digestion commencing.
I will try unplugging it and see what happens.
Will let you know how I get on.
Many thanks,
Andy

 

There are no 'outputs' from the sounder unit, so you can just disconnect it for the time being.

JimmyL: Devon David has posted his repair here somewhere.

M

 

Lots of different problems here, and like many Jaguar Electrical Gremlins, may well boil down to one small issue.
As far as I am aware, there are two types of "security sounder" (located below the headlamp on the right hand side wing (fender). The "intelligent" ones have internal rechargeable NiCads which, after 15 or so years, start to self-destruct and can cause other problems. It is possible to renew them, but not a job for the faint-hearted as they are "potted" in a sort-of rubber compound which is not like normal silicon. These will work even if a thief manages to disconnect the main battery and are linked to tilt-sensors so you can't get the car on to a low-loader or tow-truck to steal it that way. The other type - fitted I think to US cars - is "passive" so has no internal batteries and much simpler internal circuitry.
Both types can be disconnected with no other knock-on effect. Worth a try, but I don't think that's the problem here.
Gus's wiring diagrams are your friend here - and a bit of patience. It should be possible to track down the fault or at least narrow it down to a specific circuit or component.

 

Thanks everyone. I do have all the wiring diagrams so will have a look through them to try and figure it out, but first I will have a go at disconnecting the sounder.

It makes sense that if it is corroding badly internally, then it is quite possible it may create a short in the circuit and take out the fuse.

Unfortunately, time is not on my side at the moment and I'm not going to get a chance to look at this now until Christmas, but I will update the thread to let you know how I get on.

Andy

 

Andy.
You can disconnect the sounder through the small access panel in the wheelarch liner and the steering on full "left lock". A small LED torch is a helpful accessory !!

 

David, thank you, you saved me a considerable amount of time with that tip. I had no idea where it was and was looking under the air box.

Disconnected the sounder, fitted a new fuse and hey presto........Mrs C has a big smile on her face now everything is working again and the heater is doing it's thing.

I haven't had time to look at the wiring diagrams yet, but I can't see why that fuse affects interior heat supply?

Thanks to all who assisted.
Andy