Heated rear seats

[DT1]

I have just retrofitted heated rear seats to my xjr using heating pads from the rear seat of a x350 sovereign. Switches all light up and had the car on the diagnostics to programme the rear controller to make them work

There is no option for programming them in the diagnostics as they should just plug and go. All wiring loom in place, all fuses in place.

Advice please. What haven't I done

David

[BrianG]

Silly question: do you know that the heater pads were actually functional on the donor Sovereign? I would check that the pads are not open circuit, before chasing around for other more 'interesting' problems. Also depending on your year of car and the year of the donor car there may be wiring changes that make it incompatible without some rewiring. (Over on jaguarforums.com there's an owner of a 2006 X350 detailing the problems of trying to fit the front seats from an X358 and he found different pin numbers and connectors used)

[DT1]

Thanks. Don't know if they were working originally

Looks like rear seats out and a continuity check to see if elements are intact and to check the earth connections

Any suggestions how to test the heat sensor that is in each circuit according to the wiring diagram

Just think it odd neither side is working

David

[DT1]

So. Completed the electrical investigation. Full continuity though the elements for both seats. Earth connected

Both sensors show open circuit and even when bridged no power to heating elements. Rear controller is trying to put 8v onto the sensor as soon as the ignition is switched on. The heat setting on the switches does not affect this . Indeed when they are switched off the 8v is still there.

So I have concluded it may be the incorrect rear controller. Investigation shows vehicles with heated seats have a rear controller no 5w93 13b524. And mine has 2w9f 13b524. Could this be the issue?

Interesting on other forums a general theme on retrofitting heated seats that all parts installed and they don't work

Any views please

David

[davidr]

Possibly the car needs to be plugged in to a diagnostic machine to enable rear seat heaters?

[DT1]

Thanks. Have thought of that and had it plugged in. In the option list there is no option for heated rear seats. Everything else from sat nav to cd and whether you want the wing mirrors to dip when you reverse.

Might be with the different rear controller there will be more options

If I have missed the option when the vehicle is plugged in love to know where it is

Thanks again and welcome all ideas

[RichardSEL]

No immediate experience of either car to offer. Except to say that most controllers of this era were PROM (Programable Read only Memory) hard programed at their factory and can't be re-programed as would be an EPROM (Erasable Programable Read Only Memory)
Coz they're manufactured by the 50,000 (probable batch size) for worldwide distribution, there's a cost difference between both -- the more the facilities the controller offers (and the smaller the production run) the more unit cost.

Went thru all this with VW when I converted my '06MY Passat to power fold door mirrors (they're large ears and too often got crunched by passing traffic) My original controller wouldn't take them. Luckily it was a scrappy that I got the correct controllers, extra wiring loom, etc. from

[DT1]

Thanks for this information. Have tried a new rear controller and heated seats worked but no fuel gauge as it was from a diesel and had a different part number

If any members have a x350 with heated rear seats could you let me know the rear controller part no

Will be either 2w9f 13b524 or 5w93 13b524. Trying to establish if both controllers will work with heated seats or just one of them

Thank for your help