So I'm writing this because I got a wild hair after cleaning the filters on the bottom of my seats and I wondered if there was a separate filter for the backrest. Turns out there was. And it was filthy.
I also had noticed the back rest hardly blew any air at all. Through the process I discovered that the duct to the back blower was full of cracks. It looks to be made with pretty deplorable quality plastic, so I'd recommend everybody check it out if you're feeling the same windless scenario.

Tools:
Flathead (for prying)
Angle cutters (for cutting zipties)
T-20 Torx screwdriver
Silicone or other flexible goop (polyurethane or something) to fix the cheap, crappy duct
electrical tape because I'm neurotic about whether the goop is going to be enough to keep it together
Zip ties

Process:
1) Yank the bottom of the seat from the back off. It's just 3 snappy things (technical term). You can see one of mine didn't come off with the panel, but it's easy enough to yank out and put back on.



2) Pop the side panel off next to the thingamajig you just popped off. No screws or anything, just some tabs that will pop as needed. Should come off pretty easily.





3) pry the side of the seat's back panel off the very large pivot point you see in the pic. It's surprisingly easy on this side, but you have to do it on the other side. I didn't bother taking a pic of the other side because I also didn't bother taking off the outer panel there (too tough to reach). Instead, I used the screwdriver to pop it off from under that panel. It was unharmed.







Zoomed out for context.

4) Pull back on the bottom of the seat. You should feel it kinda pop loose from the snaps on the bottom. Push down on the back panel of the seat with your hands. Should release from the tabs pretty easily and you can pull the panel off. Here's a pic of the back of it so you can see what you're working against.




Snaps pop out. Tabs pop down.

5) Get your bearings. This is when I looked at the duct and saw that it was cracked. I didn't realize how badly until I saw the other side though.



6) You also need to unscrew the motor. There are 3 T20 torx screws holding it on. These are pretty easy to find, but here's the pic:



7) Unplug the power from the bottom of the connector. There's just a tab you push in that's pretty easy to see, then pull down. use your flathead if necessary.
On this step, I kinda did a dumb. I didn't realize how easy it was to remove the heater, so I cut the ziptie and pulled the duct off. DON'T DO IT! It's so much easier to just move the tabs on either side away from the unit. You can remove the duct once the assembly is out. Once the tabs are pushed away, the unit will come off easily.
In this pic, you can kinda get an idea of how dirty the filter was. You'd think they'd make a filter easier to get to. You'd also think they'd design it so it had some decent air supply.



8) Take the assembly inside and grab a beer. You're going to need it when you see the state of the damned duct.

9) Disassemble the unit by cutting the zipties.



You can see in the pic above the initial crack I saw. Now take a look at the back:





10) At this point, I started looking for parts. Turns out, you can't just order the duct; you have to order the entire assembly. This is yours for the low price of over $300 from dealer or from ebay for $130. No thanks - the expensive bits work fine, so why buy them again?
Time for some farmer engineering. Use the silicone or other goop and fill those cracks. I then used electrical tape to wrap the entire flexible area since I don't trust the quality of the plastic.



11) Do the reverse to reassemble the fan system, replacing the zipties (I left them long for the pic so they're easy to see on the pic, then clipped them before reinstalling) and put the seat back together. I'm letting it sit overnight to allow the silicone to dry. I'll give it a shot in the morning and see if it now pushes me through the windshield.



Bonus shots of labels for part numbers, etc...

 

Thanks for the DIY sounds pretty straight forward

I wonder if that is the same setup Ford uses in their heated and cooled seats? Since the filters are the same there is a chance and if so the replacement parts should be less for those that want new parts.

Edit

It appears for the super duties they used what appears to be a more robust design on the seat back with maybe a sealed filter element at the top?

 

Just did mine took 5 minutes getting the back of the seat off. On mine I had a black zip tie around the bundle of wires for the fan connector that was wrapped around the frame of the seat that had to be cut off on both. I did not bother replacing the zip ties I guess if those tabs fail the zip tie will help hold the duct assembly to the seat.

 

Out of curiosity, did your duct have a crack? Did it seem to be made of a cheap plastic too?

 

They did not have any cracks, I wouldn't call it cheap it was the soft plastic material that was very pliable. Was yours the harder less pliable type of plastic? I wonder if they did a material change between 2009 and 2011? Also the filters in the seats were not dirty.

 

It was pretty brittle, hard plastic. They must've changed the material.

 

Great post! I'll take a look at mine tonight. The seat bottom blows cold on mine for about a minute and then cuts out. The seat back hasn't worked in a while so I'm sure I have a similar issue with the ducting.

 

Thanks for the detailed write up. Looks like I found my Sunday project!

 

It took me about half an hour to do it the wrong way. This way seriously takes less than half that. I took apart the passenger side today in about 5 minutes. Fortunately the duct wasn't broken, so cleaning out the filter and blowing the unit out then reinstall only took another 10.

When you guys get into there, take a look at the weird opening at the top of the heater unit. Mine seems to just blow straight up to nowhere on both sides. Does everybody else's? I tried covering it up while it was running and the blower responded shortly after by slowing down, so it seems that would be counter productive. I'm sort of at a loss as to what that duct is for (except to waste airflow).

 

Are both upper and lower filters the same?
I think they are but not sure?
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Yep, they're all the same. In fact, I washed the lower ones, then installed them in the uppers because they were dry and I wanted to put the seats back together. When the upper filters dried, I put them into the lower blowers.

 

Sure like how you inserted the pictures in the right spots. I use to be able to do this but some kind of weird software change just blasts the pictures in at the beginning only?
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If you use the "insert Image" link in the toolbar above the comment box instead of the "Manage Attachments" button below it, then you can do that.

 

I will try that. Good suggestion.
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n8ertot,

So how's the performance after the "overhaul"?

Thanks in advance

 

Tough to say. I try to avoid using butt-dyno, but it did seem like the reaction time and acceleration were better. It's tough to say because shortly after I did it, we got our snowfall, so I haven't been able to really check out the mileage or response.

Regardless, considering the state of that fluid, I would majorly recommend everybody do it. Even if there aren't performance gains, there is definitely going to be less risk of failure.

 

Hi,
I'm new to the forum, I've just purchased a 2012 XF S Premium 3.0L and was really disappointed to find the drivers heated seat not working. The fan would kick in and then shut off.
Well after some digging, I found this post. I followed it and found the pipe had completely snapped into 2 pieces. I used loads of duck tape and gave the filter a good clean too and what do you know, fully functional heated seat! Took me 20 min all in.
Many many thanks for taking the time to post this guide!!!

 

Hi, I just fixed my seat today. Thank you very much for your instructions.

The duct was almost completely broken. I fixed it without taking the mechanism out at all. I used aluminium kitchen foil, nicely wrap around the broken part and then permanently putting it in place with silver tape.

Works like a charm now. My butt gor frozen on the chair when I tried cooling mode.

I also opened the passenger seat. There it's everything fine and works nicely.

Thanks again.
Rok

 

I was able to get to everything without removing the lower panel at the back of the seat, and only removing the side panel on the outside of the seat to give enough room to unhook just one side of the back panels lower mounts. Then it unclipped at the base and slide down to give full access.

Makes it that much easier.

 

Finished up all 4 filters yesterday. The end result was that all filters looked very clean, but I blew them out with compressed air anyway.

The duct on the passenger side seat back was like new with no cracks at all. The one on the driver's seat back was heavily cracked in 3 places. I taped it up good and put it all back together.

I am guessing it's the movement of the driver that causes the cracking since the top mount of the duct is attached to the seat and every time you lean back on the seat back, it causes the ducting to flex.

I felt around the ducts on the bottom, and they felt fine with no cracking, so maybe those ducts don't move as much.