[HOW-TO] Install heated seats (incl. Kufatec retrofit cable)

henkkeumus

Dutch Retrofitfanatic
Backstory:
Well, after seeing much information (dating 2014) but no discrete information in how to connect the retrofit cable from Kufatec I took a leap of faith and bought myself a clima-unit with heated seats option and the Kufatec loom.

After 2 days of measuring, fitting and sweating I managed to get it working. This manual will unclude the pinout for a LHD aswell as a RHD :).

The loom will come without a manual to lay the cable so the way I describe it in this tutorial isn't necessarily the 'best' one.

Tools needed:
- Clima-unit with heated seat options: 8P0820043BH XHA
- Kufatec retrofit cable (I have the 'only heated seat' variant): https://www.kufatec.com/en/audi/a3/...heating-harness-for-audi-a3-8p-8p-sport-34045
- Torx: TX25
- Inbus: M6
- Socket wrench: Size 8 and 10

Note before starting:

Since I disconnected the seats in my how-to I also disconnected the airbag connector. Just to be sure, disconnect your battery before working on this retrofit.

This how-to is done on a LHD car (I'm Dutch). It doesn't really matter, the how-to for a RHD is the same except for the pins behind the clima which I will address later in the tutorial.

What is in the Kufatec package?
- Retrofit loom
- Additional steady plus cable.

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HOW-TO:

Step 1.

Get your radio out the dash.

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Step 2.
Pull the hazard light switch trim out. It's in very firmly so a little pressure needs to be applied. I scratched my hand like a dozen of times disconnecting this trim. A true evil piece.

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Step 3.
Place something protecting over your ashtray as the clima-unit is also an evil piece that is very stuck in the dash. You need to pull it towards you and it will get loose.

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Step 4.
Disconnect and disassemble the seats. Won't go too deep into this since it's pretty straight forward. 4 bolts on the corners of the rails and the connectors in the floor.

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Step 5.
This step is kinda optional but I wanted to lay the cable in a neat and invinsible manner. So I got the midconsole out to lay the cable under the carpet.

5.1: On both sides of the midconsole there are 2 size 8 bolts. They are hiding under plastic clips who can be easily removed.

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5.2: Get your ashtray and geartrim out. Open your ashtray and get your fingers under the geartrim. It should be an easy go since they only get hold by 4 plastic pins. When the trim is out it will show you 4 TX25 bolts. Unscrew those. Since you are here also unscrew the 2 size 8 bolts on both sides.

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5.3: Now get on the ground and get your M6 inbus. On the bottom of the trims on the side there is a inbus screw hiding in place. Get that thing out on both sides.

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5.4: Last but not least there are 2 very very difficult to reach bolts hiding in the back of the dash. Please use a towel of some sort to catch the bolts as they will fall out into nowhere.

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5.5: Now on to the backside of the midconsole. Remove the ashtray by opening it and pulling it towards you. After the ashtray is out you can also remove the box under it. It will reveal the last 2 size 8 bolts. When you got those bolts out remove the armrest by bolting out the big size 18 bolt in the middle.

My A3 came with telephone preparation so there are cables on the picture. It's not certain your A3 has those, so don't bother looking for them if you don't see them :D.

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And now the midconsole can be pullet out (gently). Some cables are clipped into the midconsole so gently pull it up and check the cables (cigarette lighter, AUX, telephone etc..)

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Step 6.
Get your Kufatec loom. You will see the 2 big black plugs who obviously connect to the black ones underneath your seat. But you do I know which one should go on what side? Well, on the cable you will find imprints. Look for the biggest cable on the connector (PIN 1). It will say one of these two things: BFS or FS

FS = Fahrersitz = Driverseat
BFS = Beifahrersitz = Passengerseat

I wanted the cables tucked away in a neat way, I forced my arm under the carpet and pulled the cable from the midconsole to the connectorbox under the seat for both seats.

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Step 7.
The fun part, the connectors behind the clima unit. They are hold in place by a tie-wrap and a clip. Disconnect the housing from the actual connector to reveal the pins.

NOTE: THE KUFATEC LOOM ONLY USES CONNECTOR C AND D.
C = Bown/Goldish connector.
D = Black connector (biggest).

You can check the back of your clima-unit, the letters are stamped on the slots.

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Press the black pin DOWN.

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Step 8.
When you got the housings of pull the Kufatec loom from the midconsole towards the clima unit. Now the pinning can begin. How do you know what hole belongs to what pin number? On the actual connector itself you can find the numbers corresponding to the hole (where the pin goes into).

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Just as on the cable under the seats these cables also have imprints on them. They correspond to the pins they should go. Since Kufatec is a German company and in Germany they produce LHD cars the imprints won't correspond for UK. Check the table underneath for the correct pinout.

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LHD - Left hand drive (steering wheel on the left side of the car)

The extra cable:

T16d/14 = Connector D - Pin 14 - (Constant + driver)
T16d/13 = Connector D - Pin 13 - (Constant + passenger)

The big Kufatec loom:
T16d/6 = Connector D - Pin 6
T16d/5 = Connector D - Pin 5
T16d/2++ = Connector D - Pin 2 (is already occupied, leave it for now, will be discussed in next step).
T16c/10 = Connector C - Pin 10 - (Heat intensity button)
T16c/9 = Connector C - Pin 9 - (Heat intensity button)

RHD - Right hand drive (steering wheel on the right side of the car)

The extra cable:
T16d/14 = Connector D - Pin 14 - (Constant + driver)
T16d/13 = Connector D - Pin 13 - (Constant + passenger)

The big Kufatec loom:
T16d/6 = Connector D - Pin 5
T16d/5 = Connector D - Pin 6
T16d/2++ = Connector D - Pin 2 (is already occupied, leave it for now, will be discussed in next step).
T16c/10 = Connector C - Pin 10 - (Heat intensity button)
T16c/9 = Connector C - Pin 9 - (Heat intensity button)

Step 9.
Connector D, pin 2 is already occupied. This is right, splice the T16d/2++ loom into the existing loom. I used a T-connector for this. If you pin 2 is not occupied you can use the factory connection from Kufatec.

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Step 10.
Wire things up and put the housing back on the connectors. Use a tie-wrap to get them tight since the connector will be loose in it without!

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Step 11.
I used the right side of the midconsole to put my ground cables. The manual states under the A-column but that would require me to pull the cable all over to the other side. So I just unscrewed the plastic trim on the side and brushed some of the paint of the chassis.

Put the trim back and mounted the ground to it. Checked it with a multimeter and works like a charm.

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Step 12.
The only thing that is not connected now is T16d/13 and 14. These cables will run to a single connector which need to be connected to a 'dauerplus' (Constant 12v current). I pulled a cable from my + pole on the battery through the firewall and spliced the cables together.

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Result and testing:
Before getting everything back test your seats. Plug in the seats and connect the wires under your seat. Connect the battery again and turn your key to ignition.

It can take up some minutes before your seats will get hot the first time, but when they do it's fire :).

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Troubleshooting:
If your seat doesn't work;

- Check voltage on PIN2 under your seat. When you wired it correctly there should be a 12v voltage on this pin.
- Check the connection of T16d/2++ this is a spliced loom and can cause errors.
- Check your ground, make sure it is grounded properly!

Still having issues? Please respond in this topic and maybe I can help you out.

Best of luck!
 

henkkeumus

Dutch Retrofitfanatic
You should work in AUDI, very detailed :) , sit down, you earn your self a cookie :p

I'll do my best.
The modding scene, it's way bigger in the UK than in Holland, love it :D
 

henkkeumus

Dutch Retrofitfanatic
I currently putting original arm rest instead, so looking for missing bolt it says on diagram its this one https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/hex-bolt-priced-each/n0903168/, however it say it doesnt fit A3 8PA so i am bit puzzeled

Well, it doesn't really matter. Go to your local hardware shop and check for a M8 bolt that will fit in length. It only needs to hold the armrest :).

, btw if you are in Holland I can visit you since I will be in Brussels this summer :), I was last year in Baarle Nassau

Haha, that's ~200KM away from my hometown.

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ch1z64

C'mon you's bhoy's in Green
VCDS Map User
Silver Supporter
Excellent write up , it should help loads off guys out now and in the future
 

EvilSmurph

Registered User
Well, it doesn't really matter. Go to your local hardware shop and check for a M8 bolt that will fit in length. It only needs to hold the armrest :).



Haha, that's ~200KM away from my hometown.

0ccfd7796847f2a0b6078b506b22f9f4.png
This summer I should be again in Brussels, plan is to visit Twente and go to island Texel, so if you want we can grab a beer :)
Tnx for the tip, bought the bolt at local hardware store, so it took me around an hour to install original arm rest, which btw I bought in Holland :)
 

henkkeumus

Dutch Retrofitfanatic
This summer I should be again in Brussels, plan is to visit Twente and go to island Texel, so if you want we can grab a beer :)
Tnx for the tip, bought the bolt at local hardware store, so it took me around an hour to install original arm rest, which btw I bought in Holland :)

A beer is always a good idea :D. Hit me up when you travel this way.


Looks good.
But vacuum your car man!! :highly amused:
 

EvilSmurph

Registered User
A beer is always a good idea :D. Hit me up when you travel this way.



Looks good.
But vacuum your car man!! :highly amused:
I am waiting for nicer weather, still have winter tires, next month i will do the chem cleaning of the seats and waxing :)
In Croatia weather during winter is really bad, snow, rain and strong wind, besides on the back seat is for the dog only :)
 

AudiFan7

Registered User
BIG thanks for this thread :) I was thinking about this retrofit, but the wiring part was stopping me until I found this nice how-to. Everything is clear, except the part with pulling the 12v cable through the firewall. How exactly and where did you managed to run the cable through?
 

henkkeumus

Dutch Retrofitfanatic
BIG thanks for this thread :) I was thinking about this retrofit, but the wiring part was stopping me until I found this nice how-to. Everything is clear, except the part with pulling the 12v cable through the firewall. How exactly and where did you managed to run the cable through?
Will post a photo of the location this weekend.

You can also open your fusebox and connect it to a live feed in there (thats what I did later). The Kufatec loom comes with a cable for the constant plus that can be fitted in an empty slot on the fusebox.

The white loom is the constant plus loom. On the other half there is a constant live feed from Audi originally and they are connected with a 20A fuse. Nice and tidy.

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henkkeumus

Dutch Retrofitfanatic
Understand :)

Totally forgot to take the picture, but this video does it on the exact same spot as I did.


Watch from 7:40, there is already a thick rubber you can poke something through and then pull the cable with to the other end :).
 

henkkeumus

Dutch Retrofitfanatic
Found some pics of my earlier A3. Same spit :).

Remove the battery, that should give you plenty of working space to get it through.

BEAR IN MIND THIS IS A RHD CAR!!

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FPSUsername

B.Eng. EE
Thank you for the detailed guide.
I have leather seats like in the picture below, except they're fully white/beige:
$_86.JPG


How can I figure out if these seats have the heating mats installed? Do I have to unbolt the seats and check the connector for populated pins? (assuming that there is a connector for airbags since the seats have no electrical mechanisms).
 

henkkeumus

Dutch Retrofitfanatic

ch1z64

C'mon you's bhoy's in Green
VCDS Map User
Silver Supporter
A3 8V heated seats plugs are green, in the 8P the heated seat plugs are black
My bad then but glad someone put him in the rigbt direction plus they know whats heated in 8V cheers
 

FPSUsername

B.Eng. EE
Unfortunately, I couldn't get a good look under the seat (I think I'll have to remove it to see). I saw two wires that lead to the hole in the ground. Under the cover, I saw these two connectors (of course the third one is missing for the heated seats).

IMG_20201114_141957.jpg

I'll check again later when I decide to remove the seat, I'm not sure if I have the required tool at the moment.
 

henkkeumus

Dutch Retrofitfanatic
Unfortunately, I couldn't get a good look under the seat (I think I'll have to remove it to see). I saw two wires that lead to the hole in the ground. Under the cover, I saw these two connectors (of course the third one is missing for the heated seats).

View attachment 212441

I'll check again later when I decide to remove the seat, I'm not sure if I have the required tool at the moment.

You dont have to remove it. Your seats dont have a heating elements in them. The wires you see is for your airbags and occupy sensor (registers when somebody sits on it and when you don't clikc in your seatbelt a warning will sound).
 

FPSUsername

B.Eng. EE
You dont have to remove it. Your seats dont have a heating elements in them. The wires you see is for your airbags and occupy sensor (registers when somebody sits on it and when you don't clikc in your seatbelt a warning will sound).

Ah, that's a shame. I hoped that they'd be installed, perhaps the cable is tucked away? I only assume this so that the manufacturing process is cheaper (that's how for example, the TT MK2 chassis is the same for the FWD and AWD version)
 

henkkeumus

Dutch Retrofitfanatic
Ah, that's a shame. I hoped that they'd be installed, perhaps the cable is tucked away? I only assume this so that the manufacturing process is cheaper (that's how for example, the TT MK2 chassis is the same for the FWD and AWD version)

Hey mate, nah believe me. If you had the option you would see the cable.
 

FPSUsername

B.Eng. EE
Hello, I came to the conclusion that it is possible to fit the heating mats in the seats, but for that, I need to buy the heating mats.
I've found out, using ETKA, that there are three seat parts and then the rest of the system with the Kufatec loom.

Backrest: 8P0 963 557 D, E or F
Bottom: 8P0 963 555 F, G or H
Plus the harness to connect the two mats (no part number)

Both heat mats cost 110,50 euro excluding tax (according to ETKA).
I'm trying to source parts for at least the driver seat and see how it goes.
 

George Kost

Registered User
Hello, I came to the conclusion that it is possible to fit the heating mats in the seats, but for that, I need to buy the heating mats.
I've found out, using ETKA, that there are three seat parts and then the rest of the system with the Kufatec loom.

Backrest: 8P0 963 557 D, E or F
Bottom: 8P0 963 555 F, G or H
Plus the harness to connect the two mats (no part number)

Both heat mats cost 110,50 euro excluding tax (according to ETKA).
I'm trying to source parts for at least the driver seat and see how it goes.
Don’t forget you also need the Clima-unit with the seats buttons!
 

FPSUsername

B.Eng. EE
I most certainly did not forget about that. I am planning on going for the Q3 unit. My question is which Kufatec loom is needed, climatronic or climatic?
 

FPSUsername

B.Eng. EE
I figured out which parts I need for the seats I have (same seats as the image I sent earlier in this thread, except full leather).
8P0 963 557D
8P0 963 555F

I ordered both elements for under 100 euro (35 euro per piece) which is a steal. You'd either have to get lucky finding them on eBay or buy the chair and move the elements over (in case you have a special/less common interior like mine, which is beige)
 
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MT-V6

Registered User
You could swap the heating elements into your seats if you are up for the challenge of taking them apart. Since you have quite unusual colour seats it might be your only option. This is for a TT but I am sure the process is similar. You will need to go a step further and separate the leather from the foam, which is help in place with some metal rods

https://www.ttforum.co.uk/forum/viewtopic.php?f=19&t=1906219
 

FPSUsername

B.Eng. EE
Seems like it's indeed quite the task, but it should be doable in a weekend. I'm already glad that the leather is held on with clips and isn't stapled into the seating like an office chair is.
Thanks for sharing the thread, I could only find a video on YouTube on the 8V seats.
 

Orange225

Registered User
Stripping the seats isn’t too bad, the hardest part it removing the seat back, everything else is easy Enough to work out
 

FPSUsername

B.Eng. EE
Got the heating elements. The only issue is that I don't have the cable that goes from the elements to the Kufatec loom. I asked the dealer if the cable is available to buy separately.

RY2sLeF.jpg
 

FPSUsername

B.Eng. EE
Another update, ETKA helped me once again and found the seat harness for the heat elements. The part number is 8P1 971 381 B.
With some luck you'll find them on eBay for 30-50 euros, otherwise, you'll have to get the full harness (which should include all stuff for electrically adjustable seats if I'm correct) from the dealer, which retails at around 180 euro.
This unless you know the part numbers of the connectors and can build it yourself (finding those is a pain, like always in the automotive branch)
 
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