Retrofit Heated Seats - A Complete How-To

[Con.mc123]

Why buy the Kufatec garbage? Why not buy the Erwin connection? Seat heating uses a total of four wires. The airbag is separate anyway, a yellow connector, and the third two-pin connector is for the seat belt control.

These are all the wires under my seat. Sorry for the bad pictures, screenshotted from a video.

Honestly I bought Kufatec because everyone seems to be using it. Didn’t know Erwin connection made/ sold something like that - have you got a link so I can check it out?

Erwin (the website) doesn’t work great from where I’m from…

 

[cairus]

Erwin ist OEM Technical Documents

 

[Con.mc123]

Yea I know that, it doesn’t let me type in my VIN in my country to get the relevant data to my car and I don’t particularly want to go through 2000 pages of stuff I’m not sure I’m looking at….

 

[cairus]

Sorry, you want others to do the work for you?

 

[Con.mc123]

I’m just asking more experienced people if they know what the wires are for under my car seats…

 

[tracktoy]

It very much depends on your cars setup but from what I have read its Airbag, Heated Seats, Seat occupancy sensor and cant recall what its called but the sensor that comes from the seatbelt buckle.

I can only confirm on my 2014 car the yellow one is the airbag in the seat.

 

[cairus]

Why buy the Kufatec garbage? Why not buy the Erwin connection? Seat heating uses a total of four wires. The airbag is separate anyway, a yellow connector, and the third two-pin connector is for the seat belt control.

the answer is already there

 

[simion_levi]

@Lozzy15I have checked today with the Advanced Measuring Values and everything for both the heated seats is reversed left to right, ie the heating operation and also the temperature sensing. I followed the Kufatec wiring instructions (copy attached) and double checked prior to reassembling. [The reference to Permanent positive at fuse spot SC45 relates to the power for the powered drivers seat.] I can believe I might have got one wrong wire/pin placement but it seems difficult to understand how I might have perfectly reversed all of them left to right. My suspicion is therefore falling on the Kuatec instruction sheet.

I will pass this by Kufatec after the weekend but whatever the cause, it needs correcting. However I am very reluctant to take out the BCM in order to swop over wires bearing in mind all the trim to be removed and the difficulty removing and then reinserting the BCM. My remedy is therefore going to be a cut and splice operation involving the passenger and driver heated seat looms where they run side by side in the passenger cill. On the face of it all that is involved is cutting and swopping power cables A2 & A5 and doing the same to the control cables C40 and C43.

EDIT: @Lozzy15 I am even more confused having just checked the Kufatec intructions because they coincide exactly with your guide, ie BCM pins 5 and 40 for drivers side, pins 2 and 43 for passenger side and pin 56 common to both sides. I am also pretty sure I wired correctly to each pin because of my hand marked dash against each one done after double checking the pins/wires after installation in the BCM connectors.

View attachment 35836

I've just come up against this same issue - installed as per Kufatec instructions for RHD and believed I'd checked them off against yours, @Lozzy15, only to find the HVAC buttons activate the opposite seat!

However, I've just checked against your instructions again, and note there is a difference I missed. Your instructions keep pin 40 for driver and 43 for passenger for both RHD and LHD and only swap 2 & 5, whereas Kufatec are swapping both over. I currently have 5 & 43 as driver, 2 & 40 as passenger.

Clearly I need to get the BCM out again and move at least one set of pins, could you just confirm your position on 40 driver/43 passenger is correct and not a misprint? i.e. the power supply cables 2&5 physically move depending on driving side, but control cables 40&43 should be fixed (and therefore presumably the seat they are controlling gets set by coding/adaptation for RHD/LHD, instead)?

 

[cairus]

Kufatec ist Müll...

Write PM to me

 

[Lozzy15]

I've just come up against this same issue - installed as per Kufatec instructions for RHD and believed I'd checked them off against yours, @Lozzy15, only to find the HVAC buttons activate the opposite seat!

However, I've just checked against your instructions again, and note there is a difference I missed. Your instructions keep pin 40 for driver and 43 for passenger for both RHD and LHD and only swap 2 & 5, whereas Kufatec are swapping both over. I currently have 5 & 43 as driver, 2 & 40 as passenger.

Clearly I need to get the BCM out again and move at least one set of pins, could you just confirm your position on 40 driver/43 passenger is correct and not a misprint? i.e. the power supply cables 2&5 physically move depending on driving side, but control cables 40&43 should be fixed (and therefore presumably the seat they are controlling gets set by coding/adaptation for RHD/LHD, instead)?

The pins in the guide are correct. I found out first hand when I installed it as I had exactly the same issue, but I was using these wiring diagrams:

The pinouts on these contradict the guide and the kufatec installation notes - but this diagram is for models that are LHD, hence the pins need to be swapped over for UK cars. This is the only reason the LHD/RHD diragrams got made for the guide in the first place as this problem cropped up at the very end so I figured I'd better clarify it.

Best advise I can give is to check you've got the pins the right way round on the kufatec loom - as per Nick Bacon when he posted maybe their loom is either incorrect or has been re-designed for RHD cars but the install instructions didn't get changed? Did you get the same instruction note as he did?

Let me know what you find!

Cheers,
Lozzy.

 

[Lozzy15]

Kufatec ist Müll...

Write PM to me

Cairus, could you please be mindful with replies to other members. Just seen you previous posts in the discussion and telling people the loom is garbage isn't really helpful for them when they're asking questions. If you think the loom could have issues maybe pointing out what those issues could be and how they could fix them other than saying to buy a different loom/connector would be a more productive response.

Thanks.

 

[simion_levi]

The pins in the guide are correct. I found out first hand when I installed it as I had exactly the same issue, but I was using these wiring diagrams:

Best advise I can give is to check you've got the pins the right way round on the kufatec loom - as per Nick Bacon when he posted maybe their loom is either incorrect or has been re-designed for RHD cars but the install instructions didn't get changed? Did you get the same instruction note as he did?

Let me know what you find!

Cheers,
Lozzy.

Many thanks Lozzy, returned to it at the weekend and now have the buttons and seats correctly paired!

I removed the BCM again and traced 2/5 and 40/43 to each seat connector. Both needed swapping over to align with your circuit diagram.

By the way, it looks like Imgur has blocked visibility for hosted images in the UK today. I can still see them over a VPN, but not otherwise. Not sure if that is temporary or a response to the new age verification regulations. If you haven't already backed up your hosted photos, it may be worthwhile doing so soon - your guides are incredibly helpful!

 

[Con.mc123]

Many thanks Lozzy, returned to it at the weekend and now have the buttons and seats correctly paired!

I removed the BCM again and traced 2/5 and 40/43 to each seat connector. Both needed swapping over to align with your circuit diagram.

By the way, it looks like Imgur has blocked visibility for hosted images in the UK today. I can still see them over a VPN, but not otherwise. Not sure if that is temporary or a response to the new age verification regulations. If you haven't already backed up your hosted photos, it may be worthwhile doing so soon - your guides are incredibly helpful!

Hi,

I was hoping you could give me some guidance as I’m not completely sure what I’m doing.

When using the Kufatec loom, do you only need the 39952 (Variant 1), or do you also need the 39962 (Variant 1)? I have genuine heated leather seats, but it’s a bit confusing trying to figure out exactly what’s required, since there’s so much contradictory information out there about the wiring.

I’m planning to tackle the installation soon, but the whole 40/43 and 2/5 driver vs. passenger setup is really confusing .

Any advice would be greatly appreciated—it feels a bit daunting whenever wiring is involved .

Thanks!

 

[simion_levi]

If you have original heated seats, they should already have the large 8 pin plugs attached to the heat mats within. See https://kufatec.com/en/cable-set-seat-heating-heating-mats-for-mqb/39962, as long as you have the larger connector attached to seat wiring - next to the yellow airbag connector and small black 2 pin occupancy sensor - you should be good with 39952 variant 1.

My advice would be to ignore the Kufatec instructions and ignore the screenprinted labels on the cables - instead, use a multimeter to trace the 5 cables you need to connect to the BCM to the pins in the driver/passenger connector and then install in accordance with Lozzy's wiring diagram for RHD. Once you have glovebox out, fusebox released and BCM out, the wiring is easy enough. Getting to that stage may be a bit of a learning curve if you haven't done it before though! Not complicated, but access is tight - occasional breaks for tea, reflection and resting scraped knuckles may be necessary.