heated seats retrofit

[southpawboston]

Nice man, I got my seats in over the weekend (largely to stop hearing complaints from people in my shop where they were stored). How difficult was it to get the harness over to the passenger side? Did you pull the center console/carpet? I REALLY don't want to but if it's necessary I'm gonna sound deaden the floor while I'm in there. I have all the materials for it (MLV, CCF, etc) as I still intend to do my doors.

Running the Kufatec harness was the easiest part. From the BCM, it branches into left and right sides. Left side runs behind the kick panel and under the sill-- you only need to pop out the forward-most four sill clips, not the whole sill.

Right side runs under the carpet behind the brake/accelerator pedals along the firewall, passes through the dash to the right side without any disassembly, and continues along the firewall behind the center console to the right side. No need to pull the console. Then behind the right side kick panel and under the sill. I only pulled the kick panels and the sound insulating panels under the glovebox and steering column. Honestly that was the easiest part and Kufatec designed in at least 6" of extra length to make sure each harness branch will reach each seat.

The seat ends of the harness pass under a couple of inches of carpeting between the sill and the floor connectors. No carpeting has to get removed.

I've gotten really good at removing the BCM connectors and adding new pins, so there was no challenge there. But the biggest challenge, and one that I did not succeed at, was inserting the SC26 fuse connection behind the fuse panel. I didn't try too hard, but I gave up pretty early as it was getting late and it was the last thing that needed to get done. I ended up jumpering the connector to temporary wire hooked up to an add-a-fuse, and plugged into SC26 from the front. At some future point, I will reassess and figure out how to get the fuse wire in there properly so it will be 100% OEM.

Don't forget that that the BCM will have to get coded to recognize heated seats.

 

[Cuzoe]

That's great. I hadn't even layed the harness in the car to see if it was long enough for that. I read somebody's post on another forum that said the harness was too short. What I assume from their post was that they ran the harness along the driver side seal and then across (presumably aft of the center console, under the carpet) to the passenger side which would not be fun. Possibly kufatec started making them longer, always easy to hide slack.

If I get a chance I'll get my harness in there this weekend. I'm also retrofitting the Audi chirp alarm siren so I'll be at the BCM for that. Sadly I have a midline BCM (took pictures of pins to confirm like you suggested earlier) so that's got to be replaced before I get heated seats working. That won't be later in the summer most likely.

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[Bäsemödel]

You found out you have the highline BCM correct?

EDIT: re-reading... you took the BCM out and soldered new pins in? Is that the only limitation? I thought it had more to do with the programming of the BCM and then not having the pins was a smaller hurdle...

 

[southpawboston]

You found out you have the highline BCM correct?

Early on I stuck my cell phone in that tight space to photograph the pins on the BCM with the connectors off and map them to the wiring diagram— all the necessary pins for fogs, ambient lighting and heated seats were there. Go figure, on my lowly S. They must’ve run out of the low line BCMs that day on the factory floor.

Edit: reading your added comments, no I don’t think it is possible to solder the missing pins into a low BCM and convert it to high. I suspect entire sub-circuits are missing from the board on the lower BCMs.

I am very impressed with VW’s BCM. It uses PWM to control lots of various things, and PWM allows for very smooth, tight regulation for things like bulb brightness and heating current. Definitely state of the art.

 

[Cuzoe]

Wiring into the fuse holder is an absolute pain. The problem is getting it towards you enough to pull out the purple "rail" that retains the pins. The retainer comes out towards the driver side but the problem is clearance.

I found the easiest way to actually get the pin into the spot was to stick a long zip tie in the new spot with the same orientation as the blade of the new fuse. The zip tie will fit into the new pin just like a fuse would. Then slowly pull the zip tie out while feeding your new wire up. You should end up with the new pin in the exact spot of the blade of your new fuse.

I found this out retrofitting the reverse camera. Just getting the fuse in there took more time then the rest of the wiring for that job (liftgate down the passenger side, connected to the head unit and across to the fuse holder).

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[southpawboston]

Wiring into the fuse holder is an absolute pain. The problem is getting it towards you enough to pull out the purple "rail" that retains the pins. The retainer comes out towards the driver side but the problem is clearance.

Tell me more about the retaining rail. I know these exist on most of the connectors, but was unaware one is also used on the fuse box. Davide.bonetti taught me the zip-tie trick , but all this time I kept trying to pull the fuse pin in there without knowing about the lock rail.

Does one rail lock all the fuse pins? Or is there a rail for each row? Does it just "snap" to one side by a few millimeters to unlock then snap back once the pin is in place lick the ones on the smaller connectors? Can I see it from the front of the fuse panel? Can I pull it with fingers or does it need a tool to push/pull? Does the fuse panel have to be unbolted and moved aside to allow the retainer to slide out? I'm having a hard time visualizing what needs to be done.

 

[Cuzoe]

I'll try to get some pictures from the shop manual when I get off work. But I know there are at least 2 (maybe) 3 of these rails. They run the width of the panel, not individual per pin. The arrow shows the direction the rail comes out. You will need a tool of some type. I used a pick to release it then I pulled with my fingers.

You can get to the side of the fuse holder from the panel on the side of the dashboard (the weird shaped one that is covered when the driver door is closed). The problem is getting the fuse holder towards you enough to get to the side of it. There are three plastic clips holding it in and I then had to remove 2 or 3 screws (one of them is in the picture). Then with "finesse" I was able to get to it. To be perfectly honest I don't see myself doing it again and I'm thinking add-a-fuse fuse for the seats.

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[davide.bonetti]

I apologize. when we talked about the zip tie trick, I completely forgot about the purple locks. it was not the first time I had worked in a fuse box, so I was familiar with it.

anyway, the lock spans across a row so there are at least two of them. you "pick them out" with a pick and then pull them out.

as other people said the problem is getting clearance to pull those things out.

I managed to move the fuse box quite a bit but I honestly don't know how I did it. and putting it back was even worse. I clearly remember cursing at myself "why did you ever pull this thing out", because it just wouldn't go back in its place and I started feeling discouraged.

if you feel like doing it, just know that I removed pretty much everything around the area, so OBD connector, headlight switch, BCM...

check the picture. if you zoom you can also see one of the purple locks on the left side of the fuse box.

if you compare it to the standard position, you'll realize the fuse box can be moved quite a bit... but again, don't ask me how


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[SKIN1]

I have edited this post like 10 times.

Not sure if my new BCM (5Q0937087S) is the correct one. It does not have B43. That is the only one it is missing. Do we know that B43 is required?

 

[Cuzoe]

I can't answer your b43 question, I still haven't picked up the BCM needed for me to complete this retrofit. I routed the harness but have not pinned it yet, it's just coiled up over there.

Where did you get the part number for the BCM you picked up? If you're on parts.vw.com it is possible, though inconvenient, to decipher which BCM part numbers are suitable replacements for others. But the easiest thing to do is give the dealer your VIN and have them look it up, their system will only spec a high line replacement. I don't know of any other way to be sure.

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[LozzyJ]

Hi guys, I've jumped over from a Seat forum as I'm going to be retrofitting the heated seats into my MK3 Leon (Same process as with your golf's).

A quick question if I may, to actually remove the fuse box, is it secured with just bolts or are there also clips hideen behind as well?

When you added a circuit to it what type of terminal did you use to clip in from the rear of the fuse side? I've found what I think will work (SPT Style terminal) but would like to compare to what you guys have used just to confirm.
Thanks!
Lozzy

 

[Reaper1]

Hi guys, I've jumped over from a Seat forum as I'm going to be retrofitting the heated seats into my MK3 Leon (Same process as with your golf's).

A quick question if I may, to actually remove the fuse box, is it secured with just bolts or are there also clips hideen behind as well?

When you added a circuit to it what type of terminal did you use to clip in from the rear of the fuse side? I've found what I think will work (SPT Style terminal) but would like to compare to what you guys have used just to confirm.
Thanks!
Lozzy

Just use a fuse tap, will save you probably hours of messing around with the fuse box.

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[LozzyJ]

Just use a fuse tap, will save you probably hours of messing around with the fuse box.

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I got it sorted thanks. I don't know if the fuse box is attached a bit different to the golf, but it took 5 minutes to get it loose and release the purple retaining rail

Got them all wired up and working, thanks to everyone in this thread as some of the info has helped me out

 

[LozzyJ]

Just a quick question please guys.
For those who have fitted it, are you in left hand drive cars? All the info I've found indicates drivers side to pin 2 on connector A, and passenger to pin 5 on contort A (for power this is), mine are working fully, but the buttons are opposite i.e driver button operates passenger seat and vica versa, as I'm in a right hand drive car, I'm guessing all the info and electrical schemes I've found all relate to left hand drive cars so I should have put the drivers pin to pin 5 and the passenger to pin 2.

 

[LozzyJ]

Incase any of you guys are fitting this, I've written a detailed guide over on the Leon forums. The wiring part and coding will be the same as the golfs, obviously the HVAC module is different. Feel free to give it a rear, might help:
https://forums.seatcupra.net/index.php?threads/retrofit-heated-seats-a-complete-how-to.457156/