Retrofit heated seat

[flashmandv]

I MADE IT!!!

Damn it was tough but it all worked at the end.
So the missing part was the VCDS coding. I finally did it by going to the Centr. Electronics 09 -> Coding -> LongCoding Helper.
Then on 12th byte I set the two bits for the heated front seats and the old value 80 became 83.
And voala - when pressing on the climate panel heated buttons - the BCM1 module tries to power the seats and if it does not find heating pad resistance - it shuts off.

20190207_175012 (1).jpg

Next was the temperature sensor. It seems that If I don't connect the sensor (or a resistor to hardcode its value), the heating pads are working and the measured temperature is ~-55 degrees Celsius.
If I however connect 15kohm resistor, the measured temperature is 11 degrees. 10 kohm makes it 20 degrees.
I soldered the 15kohm resistor and it seems it is all fine.

20190208_125937.jpg
(This menu is located in Central Electronics -> Measuring.. -> Channel (Group) 60 (left front seat) and 61 (right passenger seat)

My ebay mats are connected in parallel (not in sequence as the OEM ones) as otherwise they heat very very little. Their resistance is 7ohm (each), so wired in parallel it is 3.5ohm.

They are also not wide enough..but I'll have to live with that..I'm not sure why..they were supposed to be for Audi A6 4G..
I also wonder if the current is high enough. It is 4.8-4.9 A (if somebody can tell how much is the OEM current, it will be interesting to see).

Here is the seat wiring and soldering (I've cut the original kufatec connector):
20190208_121803.jpg

Here is the beta test I made:
20190208_125612.jpg

Next week I'll leave the car to a professional to install them.

I hope this "tutorial" can help somebody else.
Good luck everyone.

[KameleonicDNB]

Hi, Did these work for long or are they still going strong, Im thinking of doing the same? Great tutorial by the way.