E91 Memory Seat Retrofit

swiftryanswift · 07-28-2020, 12:53 PM

Firstly, my apologies, this has been discussed a lot over the last 10 years and i've done a lot of research, however people haven't shared their trade secrets. Not all of them at least.

I have an 2010 E91 SE, which has heated seats but no IDrive, I've bought some M sport, heated, leather, electric, memory seats. I want to retrofit them which I understand is possible, but i need a little help. They are from a Pre-LCI car so i need to swap over the airbag headrests.

Starting with my drivers seat, the wiring pins i have available are 1,5,8 & 9. The new seat has K Can, so has 2,3,4,7,8 & 13.

My plan so far is to
- merge pins 8 & 13 on the donor seat and connect to pin 8 of the existing harness. This gives me a ground.
- Connect pin 7 on the donor seat to pin 9 on the existing harness. This should give me bolster power.

It's just what i do with the remaining wires that i get stuck with.
What do i need to do, in order to wire in the rest?
I've attached a wiring diagram to show what is left.
I'm based in Cheshire if anyone wants to come and help? However i would appreciate any advice.

The wires on my harness are 1 PWM Heat & 5 Ignition Plus Heat.
On the seat i have 2 & 3 for the K CAN and 4 for Seat Heat Module.

I could live without memory seats if that simplifies things? But need the seat heating functionality.

Thanks

swiftryanswift · 07-30-2020, 11:57 AM

So further research has given me a strategy to try, but would 100% appreciate input from others

To keep my car connector the same, the work will be done to the donor seat harness
- Join Pins 7 & 4 together (Keep Pin 4 connector)
- Move Pin 4 to Pin 9 location (currently empty)
- Join Pin 13 to Pin 8 (Joint ground wire)
- Connect Pins 2 & 3 into a new Wire Terminal Connector
- Join new connector pins 2 & 3 to nearest K CAN H & L
- Fit the seat.

This will make pins 1 and 5 on the cars existing connector redundant, but as the K Can should be passing the signal for the heat seating that should be okay? Fingers crossed.

Red Racer · 06-18-2021, 11:15 AM

https://www.e90post.com/forums/showt...+seat+retrofit

I used this thread in the forum to help me... good stuff...

Red Racer · 12-05-2021, 10:13 PM

The LED module I originally used started to give me issues. So, I went back and re-worked the solution. I started with a timed relay module...

https://www.amazon.com/dp/B07T3KCQZB...roduct_details

This allowed me to program the relay to turn on for 3 sec and turn off for 3 sec. I found that at 5 sec, then 4 sec intervals didn't re-activate the seat module. 3 sec seems to work continuously. It also gave me a higher amp rating which is where LED relay was failing.

Keep in mind this relay module is for 12v options and the seat only likes 5v. So, after the relay, I reduced the voltage to 5v by using a common Buck regulator set for 12v to 5v. There are many options out there... This is the one I picked.

https://www.amazon.com/DROK-Electric...758521&sr=8-17

Now the seat works continuously without any issues. Hope this helps.

07-28-2020, 12:53 PM	#1
swiftryanswift Registered 3 Rep 3 Posts Drives: E91 320d SE Join Date: Jul 2020 Location: Cheshire iTrader: (0)	E91 Memory Seat Retrofit Firstly, my apologies, this has been discussed a lot over the last 10 years and i've done a lot of research, however people haven't shared their trade secrets. Not all of them at least. I have an 2010 E91 SE, which has heated seats but no IDrive, I've bought some M sport, heated, leather, electric, memory seats. I want to retrofit them which I understand is possible, but i need a little help. They are from a Pre-LCI car so i need to swap over the airbag headrests. Starting with my drivers seat, the wiring pins i have available are 1,5,8 & 9. The new seat has K Can, so has 2,3,4,7,8 & 13. My plan so far is to - merge pins 8 & 13 on the donor seat and connect to pin 8 of the existing harness. This gives me a ground. - Connect pin 7 on the donor seat to pin 9 on the existing harness. This should give me bolster power. It's just what i do with the remaining wires that i get stuck with. What do i need to do, in order to wire in the rest? I've attached a wiring diagram to show what is left. I'm based in Cheshire if anyone wants to come and help? However i would appreciate any advice. The wires on my harness are 1 PWM Heat & 5 Ignition Plus Heat. On the seat i have 2 & 3 for the K CAN and 4 for Seat Heat Module. I could live without memory seats if that simplifies things? But need the seat heating functionality. Thanks Attached Images
	Appreciate 0 Tweet Quote

07-30-2020, 11:57 AM	#2
swiftryanswift Registered 3 Rep 3 Posts Drives: E91 320d SE Join Date: Jul 2020 Location: Cheshire iTrader: (0)	So further research has given me a strategy to try, but would 100% appreciate input from others To keep my car connector the same, the work will be done to the donor seat harness - Join Pins 7 & 4 together (Keep Pin 4 connector) - Move Pin 4 to Pin 9 location (currently empty) - Join Pin 13 to Pin 8 (Joint ground wire) - Connect Pins 2 & 3 into a new Wire Terminal Connector - Join new connector pins 2 & 3 to nearest K CAN H & L - Fit the seat. This will make pins 1 and 5 on the cars existing connector redundant, but as the K Can should be passing the signal for the heat seating that should be okay? Fingers crossed.
	Appreciate 0 Quote

06-18-2021, 11:15 AM	#3
Red Racer New Member 2 Rep 9 Posts Drives: 2015 F10 M5, 1991 E31 V12 6sp Join Date: Jun 2021 Location: Thousand Oaks, Ca iTrader: (0)	https://www.e90post.com/forums/showt...+seat+retrofit I used this thread in the forum to help me... good stuff...
	Appreciate 0 Quote

12-05-2021, 10:13 PM	#4
Red Racer New Member 2 Rep 9 Posts Drives: 2015 F10 M5, 1991 E31 V12 6sp Join Date: Jun 2021 Location: Thousand Oaks, Ca iTrader: (0)	Update... The LED module I originally used started to give me issues. So, I went back and re-worked the solution. I started with a timed relay module... https://www.amazon.com/dp/B07T3KCQZB...roduct_details This allowed me to program the relay to turn on for 3 sec and turn off for 3 sec. I found that at 5 sec, then 4 sec intervals didn't re-activate the seat module. 3 sec seems to work continuously. It also gave me a higher amp rating which is where LED relay was failing. Keep in mind this relay module is for 12v options and the seat only likes 5v. So, after the relay, I reduced the voltage to 5v by using a common Buck regulator set for 12v to 5v. There are many options out there... This is the one I picked. https://www.amazon.com/DROK-Electric...758521&sr=8-17 Now the seat works continuously without any issues. Hope this helps.
	Appreciate 1 johnnyorange66.00 Quote