So there are something like 10, maybe 20 or more threads on the X300 memory seat issues at this point I think

And like many others, my memory seats don't work. And while I've read the related TSBs, I haven't taken the time yet to dive into any of the more complex troubleshooting such as testing continuity/impedance of the potentiometers, etc.... but I've done some simple testing that has me wondering if it offers any clues into what it really failing with these systems.

So, like most of you, my power seats work fine manually, however upon setting the memory (1,2,3) and selecting the memory setting or disarming the car with the associated (1 or 2) remote the seat will not return to the memorized position. That's not a surprise given most owners' experiences.

Also like most of you, my memory side mirrors and steering column do work fine associated with all three memory settings and the remote.

But here's an interesting twist, while the seat cushion and back are not responding to the memory settings, my headrest does.

Now, I've also done the basic seat potentiometer test, which requires moving all seat positions to their extremes and setting the memory. According to the TSBs, if the LED lights and the memory chimes, the potentiometers are working and not out of range.

Also what is interesting is that as a test I put in a salvage seat memory controller. When I did, and then pressed the three memory buttons (without setting them), the cushion and back moved to some memorized settings, albeit extreme such as almost all the way up to the steering wheel.

Once I then set the memory settings on this replacement seat controller however, they never worked again and the previously set positions were gone.

Isn't this odd?

So let's recap:

- my seat controls work 100% manually, so the switches seem fine
- my seat memory does not work
- my seat memory LED lights and chimes for all extremes of all adjustments
- my seat headrest memory DOES work for all three memory settings
- my mirrors and steering column memory works
- I replaced the seat memory unit, and it initially had memory settings that worked, then once set the memory settings no longer did


BTW, the circuit board traces on my original seat memory unit were not worn anywhere, which I understand was an issue with some of the units.

Does any of this in combination provide any clue into what is not working with these memory units?

Interesting if nothing else....

 

my memory didn't work forward or back, but did work up/down/tilt.. then for a while they did. And, now back to everything but forward and back. I have a replacement switchpack (mirror stalk is broken off mine), so maybe I'll have a similar experience as you when I replace it.

It was so nice when it worked.

My auto exit slides all the way back, too. I like my old Cadillac - you could set where you wanted it to stop on exit as not to crush anyone in the back seat.

 

Heh, yeah I just about "crushed" my son's legs the other day. He wasn't expecting it to come back, and keep going when I turned off the engine.

He usually rides in the passenger seat, so that was a shock

It actually is somewhat dangerous. I pinched my laptop case pretty severely when it fell down and got rammed up under the seat. Nothing bad happened, but something like that could damage the item doing the "jamming" or the seat in theory. It doesn't appear to have any sensor for resistance to stop it.


.

 

I have the "L", seat going back is not a problem for man nor beast nor lap top! I was a bit disappointed in that the seat memory functions worked fine when I bought the car and ceased working the next day. As most the wheel, mirrors and seat going back with key off work fine but seat position fwd with key on won't nor will any of the memory buttons change the seat.

 

Tapping the brake pedal is supposed to stop rearward movement. Works with mine.

 

Hi Al,
I don't have memory seats, so have no first hand experience, but from your diagnostic description, the logical conclusion would seem to be that there is no power supply coming from the memory controller to the motors in the seat base. Fuse?, broken wire? or fault in the interlink with the brake pedal referred to by mgb4tim (although surely they wouldn't treat the headrest motor differently?)?
Just a thought.

 

I have fixed the seat memory on 2 cars before.
More than 90% of the broken memory is related to the potentiometer.
The potentiometers are made of plastic and really weak, once they are broken they start to spin freely, that is why the memory sometimes works and sometimes doesn't.

I have written up the procedure of fixing, but it is all written in Japanese... So I will translate it in English and upload here.
Please allow me some time.

 

Pleeeeeease!! (Thank you!!)

Are the potentiometers all the same, or different parts?

 

Here is the procedure of how to fix the seat memory.
Please forgive me in advance, my English might be poor in some parts!

The potentiometers are the same except the headrest one, which seems more durable than the other ones and which you won't have to fix.
Please refer the document.


The pdf file can be downloaded from the link below
HOW TO FIX X300 SEAT MEMORY

Please click this button in the page above;




Please use this file freely, so if it is convenient to upload the file to another English site, somebody please do so.

 

Thanks Japthug; very detailed and your English is excellent !

 

No luck opening it on my iPad, I'll try on the computer later.

 

Thanks I'll check the document at home Appreciate the help!


Question though, the Jaguar TSB on troubleshooting the potentiometers says that if one moves the seat in all directions and tests pressing the memory function at all movement maximums/extremes and the "chime" goes off and the LED lights on the switchpack, then the potentiometers are OK.

Do you know if the failure mode your fix addresses would still have the "chime" and LEDs working properly, or would they fail as the TSB states is an indication of a broken potentiometer?



.

 

Interesting, another Jaguar "easter egg" that I was unaware of

....I'll give that a try in about 10 minutes!

.

 

Worked with mine this AM, I was somewhat amused I didn't know this!

 

They usually fail at the test as the TSB states, but sometimes they pass the test even though the potentiometer is broken, because the broken potentiometer spins freely and sometimes they can be in the appropriate range.


The test only shows that the voltage from the potentiometer is in the certain range, it doesn't prove that the potentiometer is constructively sound.


I do believe most of the potentiometers are broken due to its constructive problem. If the seat movement is odd, it would be better not to believe the test if it rings and shows red LED lights. The potentiometer must be broken then.

 

Did it work?

 

Yep, works on mine too. Neat discovery.

But there is a caveat: If like me you have your foot on the brake when you turn the car off, that will not keep the seat from moving back. You will have to release the brake, then tap it again to stop the seat.

.

 

Yup, you learn that quickly when your daughter is getting crushed...LOL

 

Hello. Just to add my 2 cents worth. I have found that my front seat has a memory that works ONLY when the car is left out and is cold. Like 14 F. It will not work when it warms up. I would like to hear what you think of that please. I have full function of the steering, side mirrors. even when it is warm. I don't know what in the seat module could be affected by the heat and still work when cold. Something to think about?
Thanks
Paul
Barrie Canada.(cold)

 

the plastic and metal band may "tighten" up when cold allowing the potentiometers to grab the gear and work but expand their grip when warm not allowing them to work, just a thought.