8V RS3 seats in 8P A3

[Robin Chandler]

I've already fitted the seats earlier this year and have only just got around to wiring the heated seats up.
I've used the Kufatec loom, new climate unit with heated seat switches and got hold of the connectors for the seat.
At first nothing worked, seats not getting hot and throwing fault codes. After reading 100s of threads about retrofitting the a5/s5 seats I have discovered that it needs a relay in place under the seat to make the back part work. I have unplugged the back rest under the seat and the base now work as it should. Gets nice and hot and no fault codes now.
My question is, does anyone know how to wire the back bits up with the relay? I have searched loads of threads but can't find a way to do it?
Thanks

 

[Korben007]

Where r the photos?

Sent from my XT1650 using Tapatalk

 

[Robin Chandler]

 

[ch1z64]

might be worth a read especially the diagram part ( https://www.audi-sport.net/xf/threads/heated-seats-retrofit-installation-help-audi-a3-8p.138033/) might help

 

[Robin Chandler]

Cheers, have looked at that one.
The problem I have looking at other threads is that the 8V seats (or S5) have a different way at wiring them. The 8P ones use some kind of feedback to the climate unit that read the voltage. The bottom seat is wired as normal and works fine. As soon as you plug in the backrest it sees a different voltage and turns it off. People get around this by putting a relay in for the backrest that has a switched 12v. I'm not sure if I can just put the relay in so that when the bottom seat comes on the relay switches the backrest on. Then when the climate reaches the correct temperature it switches off which also activates the relay and turns off the backrest.
I'm hoping it's as simple as that but I'm worried that because the backrest is controlled by the seat base it might overheat.
I don't want to damage the heat pad by overloading it.

 

[Robin Chandler]

Ok, so I wired a relay in getting the switch from the bottom part of the seat and a permanent live through the relay for the backrest. All is good and gets nice and hot. Checked on vcds and they heat up to the desired temperature then turn off.
One thing that's bugging me though. Is the left hand roller for the heated seat supposed to control the drivers seat and the right hand one the passenger? Seems back to front to me!

 

[ch1z64]

In the Q3 CC post there is a bit about that problem if i mind as the CC the person bought was for a LHD car and they had to change something in VCD's