E39 Electric Memory Seat Install Guide
This is a guide on how I fitted electric memory seats to my 1997 E39 Touring that came with standard cloth manual non
heated seats.
I have fitted the electric memory seats WITH sleep power cut-off to the memory seat which is as OEM factory fitted
apart from the switched ignition on F5 which I have used F19 for.
Lately I have received numerous PM's and emails from people that want to install memory seats so I thought I do a little
write-up.
Apart from tools you'll need the following:
1. E39 5-Series
2. A set of memory seats
3. Drivers door wiring loom from a car with memory seats.
4. K72 relay P/N: 61.35-8 365 960
5. Four blade fuse holders
6. Memory switch pack
This is the K72 relay:
It has 5 contacts that need to be connected:
2. Ground/earth
4. Output to memory seat via fuse 13
5. Input from GMIII (Pin 19 on X254)
6. 50A +ve feed. 80A on post Sept 1998
8. IGN feed (fuse 19)
Drivers door loom with memory switch pack connector:
Chopped this out of a broken E39 for the blade fuse holders:
Memory switch pack:
First install the drivers door loom and the memory switch in the drivers door. White connector is for the memory switch
and the yellow one for chromatic mirror (if present)
Note the P-bus wire (thinnest of the two) as you need to trace it back into the car and find it behind the bonnet release
handle passing the LKM/LCM.
You'll need access to the rear and side of the fusebox above the glovebox, main fusebox below the drivers seat, earth
points below drivers seat and passenger seat and lastly the relays behind the steering EWS.
After a few hours it'll look like this... nice..
I'll start off with the passenger seat as it only needs two wires connecting and it's closest to the fusebox. +ve and -ve. If
you have heated seats already then you only need +ve.
You'll need to add the +ve to slot number 6 and -ve to slot number 1 in the seat connector.
The -ve wire is relatively short as the earth points are under the passenger seat
All cables are routed through the plastic cage in the sill. -ve to the earth point and +ve to fuse holder number 10 as per
factory install.
Solder the +ve wire to the fuse holder, retract the plastic retainer in the fusebox and slot the wire in position F10. It's
key to remove as much as possible around the fusebox so you can spin it round. These holders go in easily but do not
come out.
The input to F10 is already live so only the output wire to the seat is needed.
That's the passenger seat done. Next up is the drivers seat.
The drivers seat only needs three wires. +ve, -ve and the P-bus wire.
You'll need to add the +ve to slot number 6 and -ve to slot number 1 and the P-bus wire to number 4 in the seat
connector.
The P-bus wire needs to be connected to the P-bus you've traced back in the footwell discussed above. Solder it on
rather than crimping so you can always de-solder it and revert the install.
Connect the -ve to the earth point under the drivers seat and from the second earth point run a cable to pin 2 on the
K72. Open up the fusebox and run a wire from the 50A spare fuse to pin 6 on the K72. Lastly, run the +ve from the seat
all the way to F13 output in the fusebox (glovebox).
Now the easy part is over it's time to wire the K72 relay up
You'll need to pull three lenghts of wire from the fusebox (glovebox) to the K72. I wanted it like a OEM install so routed
them with the main loom near the front windscreen. This is where you'll spent wasting most time
Wires ready to be connected up:
The K72 needs an ignition feed which we will take from F19 as that's already fed from IGN and goes to pin 8 on the K72.
It also forwards the power coming into pin 6 to pin 4 so from pin 4 it's need a wire to F13 input (top)
Now there's only one wire left which needs to be connected to the GMIII in order to send a sleep signal to pin 5 on the
K72. The wire needs to be connected to pin 19 on the X254 connector (black 20-pin) to the GMIII.
Now all five wires are where the K72 is going to live it's just a matter of connecting them up
I'm sourcing an OEM relay seat but for the time being the yellow spade connectors will do
Put the car back together and stick a 30A fuse in F10 and 13 and a 5A fuse in F19, connect the battery and code the SA
function to the car with NCS Expert.
