Issues with Heated Seats Retrofit

[xxk]

Hi all

Over the weekend I attempted the heated seats retrofit on my partner's Mk5, I ordered a kufatec harness from ebay for a 2007+ seat, with adjustment. I've used the guide on the forum (https://www.mk5golfgti.co.uk/forum/index.php/topic,62645.0.html) as my reference, I also chose to extend the harness rather than swap the harnesses on each seat around.

The harness is all white with labels printed on:

Fuse board
1x ZUENDUNGSPLUS KL.15 (Thin wire - Ignition on wire..?)
2x Steady Plus (Thick wire - Lumbar Power)
1 x SC 50 KL 30 (Thick wire - Heated Seats Power)
1 x ST.C PIN 1 (Thin wire - Pretty sure this is CECM Connector C Pin 1)

HVAC Panel - Climatic
1x Blau/Rot (Thin wire, double crimped - Driver side switch)
1x Blau (Thin wire - Passenger side switch
1x ZF. KLIMA (Thin wire - CECM connection cable)

Ground
2x Thick cable

I've got power going to the seats, measuring 12v at passenger seat connectors and control module, and the lumbar support is working (although I've seen this just needs power).

I've coded in with VCDS and had a look on the measure values, Seat Heating shows as Inactive except for about 3 seconds after I turn the engine on when it shows Active, just turning ignition on it shows Inactive.

I had to wire the heated seats cable to fuse #22, as this is the only constant/unswitched supply free on my fuse board. I wired the ZUENDUNGSPLUS (ignition cable?) to fuse #6 as again #4 is used and #7/#8 have no supply. Fuse #6 is switched/ignition only.

For lumbar I've used #31 as this was unused, it's a switched supply but seems to be working fine.

As the heat isn't coming through and it's showing as Inactive on VCDS, has anyone got any ideas for what I might be missing or what I've messed up in the wiring?

Cheers

[xxk]

Updating so if anyone else attempts the retrofit and has issues there's another diagnostic thread.

After spending another day on it I'm pretty sure the seats themselves are broken or dodgy. I ended up swapping the seats out into my GTI with heat from the factory and shock, they didnt work, equally bringing my GTI seats into the standard golf they did work! Should've tried this first but never mind

Before doing this I tried the following steps:

As I was getting 12v at the seats I considered that perhaps not enough current was getting to them to actually fire them up so I started measuring voltage drop to calculate current draw from the seats when active:

I measured voltage drop on the fuse (between the two pins) with different seats switched on  with the engine running.

Standard Golf:
Both switches off: 0.0mV ~ 0A
Driver on: 2.9mV ~ 1.7A
Passenger on: 7.8mV ~ 5A
Both on: 10.8mV ~ 6A


GTI:
Both switches off: 0.0mV ~ 0A
Driver on: 9.9mV ~ 6A
Passenger on: 11mV ~ 6A
Both on: 20.9mV ~ 12A

As the standard golf was running a much lower current I tried running off different fuses, even trying my main AC fuse which was drawing 30A current. This still gave the same reading so I figured the seats themselves weren't drawing enough current. On swapping seats with my GTi, everything was reversed (seats didn't work in GTI and GTI seats worked in the normal Golf).

Think I've concluded that the current draw is down to the seat and not the actual car.

Hope this helps someone in the future too! The actual retrofit and everything isn't bad at all, just be careful the seats you buy actually work. I'm not qualified in anyway to talk car electrics so perhaps this is all a lot of dog, but I think if your current draw looks like the GTI ones listed above then you'll probably be good.

Time for a beer 

[akbarirfan]

Thanks for the update.

Did you resolve the issue with the standard seats? Or is it a case of buying a known working set of heated seats?

[xxk]

Unfortunately not, just sold them on at a loss as leathers with burned out elements.
Think if you're gonna get some then ideally you'd test then and there. Maybe do the wiring first and then try the seats at the seller's as condition of purchase.