Good write-up! I was just thinking about that since my drivers seat seems to be malfunctioning. I'd just like to contribute that harbor freight has an awesome amp meter that plugs into the fusebox to measure draw for like $15. I just used it to troubleshoot another circuit.

 

Update- I looked up my own thread, since I'm doing this to the XJR today. BTW, the XJ8 has had great seat heat ever since I took out the thermostats with no problems.

 

Another update- the XJR is burning my thighs off! Same year and model as my XJ8 but very different heat. I may have to install a resistor or potentiometer to cut the current flow.

 

Hi there,
Appreciate all the comments and help on the forum.
(I am very new to the Jaguar world - I am used to classic minis - somewhat smaller and easier I think. One extreme to the other! )
Probably being really thick here , but how do you get the seat cover off the front seat to get to the sensor? I cant see a way of un-hooking anything under the seat. Do I need to somehow remove the seat back?
Many thanks,
Richie.

 

Down at the very bottom back corners of the seat cushion, there are some black metal spring clips. Push them off with a screwdriver, then you can unfold the corners of the material. Then you need to pull the back of the seat material over the edge of a lip. There's a plastic channel sewn into the material, and it clips over a metal rail.

To access all this, move the seat as far forward as it goes, also lean the seatback all the way forward.

 

I have a 2001 XJR, and I pulled the seat cover back as shown in avt007's first post, but all I could find was one red wire bundle way off center that leads toward the front of the seat (see picture below). I felt around, and pushed down on the fabric/foam "sandwich" near the back/crotch of the seat, but didn't feel anything but foam. I could not find any thermostat switches. I did slip my hand more forward under the seat cover, and I did feel the wires for the heater, but no thermal switches. Does anyone have any more details?

All my seat heaters worked just fine last winter, but now my driver's one seems not to work, and my passenger one seems to only work on the seat back, not the seat bottom. My rear ones seem to work, but they were never very hot anyway. It is about 50 deg F outside, so not very cold. Are they at all tied into the external temp sensor of the car? Might they work beter when it's colder?

I checked he 25A fuse in the #18 slot in the RH heelboard fuse box, and it was fine. I looked under the seat front and rear, and saw the brown relay, but all wires and connections seem to be fine.

My last attempt was these thermostat switches, but I just can't find them.

(in the photo, ignore the red on the leather...it's just a reflection)

 

I dont know what to say. Post #11 says there should be two thermostats in your car. They are inside the cloth "bag" but they are easy to feel since they are round and metallic.

There is no connection to outside air temperature. I would keep looking for the thermostats.

 

Hi Rob (Avt007)
I purchased the seat heating elements (they are from 1998 XJR). I removed the thermostats by opening the cloth and replace them with 15 amp fuse.

I had to dislodge the wires a little bit, now I need to reglue the bag and the wires near where the thermostat was located.

What glue product do you recommend for this?

I removed the fiberglass shell on the front seat back and plugged in the element for the seat back, I also plugged in element to the connector under the front seat.

I had to put in the relay under the front seat.

Both of the heating elements tested OK.

Do I have to remove the front seats to remove the leather so I can glue the heating element on the seat foam??

Jim Lombardi

 

Hi Jim,

When I cut the bag open to get at the thermostats, I just left it that way, and didn't glue it closed.

I'm a little confused, though. Are the elements working when you tested them outside the seat?

And is the next step installing them under the leather? I've had no experience doing that, but I have removed seats before and it need a big Torx bit and some muscle to get the bolts out.

 

Yes Rob - I tested the elements outside of the seats. I had to remove the fiberglass seat back panel to access the electrical connector for the heating element (gray connector).
The next step is to install them under the leather.
Looks like they were glued to the seat foam.



The left one is for the seat cushion and the one on the right is for the seat back.

Note the broad yellow color of the glue (both side borders) where they were attached to the seat foam.

Jim Lombardi

 

I'd be tempted to just put them in and forget the glue. I'm not sure what kind of glue you'd use to be honest.

 

(Note the broad yellow color of the glue (both side borders) where they were attached to the seat foam.)

Jim - I am doing this mod as well, and I was told by a friend who does interiors that it is normally a double sided tape that is used. Glue won't stick to the foam adequately, especially over time. He uses a 3M product that's quite thin, so I will be going by his shop to see what it is and get some. He's been using it so long he couldn't remember any info, but it gives me an excuse to go by there and maybe watch him recover a seat....

 

Back elements we burned in both of my front seats, ended up buying kit from amazon and replaced all four pads. These already have sticky tape on them.
To connect these in parallel (original were in series) plugged both into bottom heat pad connector and "shorted" back pad connector.

this is the set (but I think it was cheaper when I got it):