Raghza

Hello
Since there are a lot of guides about retrofitting the comfort seats and they are all different, I decided to write my own. Hopefully it will help somebody

Introduction

This guide is for replacing the heated semi-electrical (with only electrical backrest adjustment) seats with the heated comfort seats (no ventilation or active seat function) on a pre-LCI E60/61 (up to 09/2005) with no PDC.
If what you have is different in any way, please do not follow these instructions directly as there will likely be some differences.
So, just to be clear, we are throwing those heated seats out of a pre-LCI (up to 09/2005) E60/61 that does not have PDC:


And we replace those with heated comfort seats that also came from a pre-LCI (up to 09/2005) E60/61:


That’s a lot more buttons and a lot more comfort!

This is what the buttons do:
- Top left, round 4 way button - lumbar control, inflates/deflates the air controlled bags behind your lower back;
- Top left, 2 buttons - width of backrest side bolsters;
- Lower left – extend or retract thigh support;
- Lower middle – moves in 6 directions: forward/backward moves the seat, up/down raises or lowers the seat, tilt forward/backward tilts the seat accordingly;
- Lower right – moves in 4 directions: up/down raises or lowers the headrest, tilt forward/backward moves the backrest accordingly. The two buttons on it move only the upper part of the backrest;
- Memory buttons – when you want to save the current position, press M so it lights up and then the number which you want to use. To move the seat to a preset position, press the number. To stop the movement, press the number again.

I know what I’m doing

If you are just looking for information about the wire connections and don’t need step-by-step instructions, then here you go:

1) Comfort seat big yellow connector, pin 2 – connect to pin 3 in SZM module’s (in the centre console with heated seats and DSC button) bigger connector. That’s the K-BUS wire.
2) Car-side big yellow connector, thick brown ground wire – move this wire to the black connector under the comfort seat (connected to the seat module). The same thick brown wire is already there, so remove it from the connector and replace with the one coming from the car-side big yellow connector. Then splice the wire and add a wire to comfort seat big yellow connector pin 11.
3) Car-side big yellow connector, thick red/green + wire – move this wire to the black connector under the comfort seat (connected to the seat module). The same thick red/green wire is already there, so remove it from the connector and replace with the one coming from the car-side big yellow connector. Then splice the wire and add a wire to comfort seat big yellow connector pin 3.

That’s it with the new wires. Connect all the connectors and you are done. Your seats should now be able to move via computer (INPA/ISTA etc). Test it out and if it doesn’t (or works partially), check the wires and the connectors. If everything works, move on to coding:

1) Add $456 for comfort seats and $488 for lumbar support to FA.
2) FA_WRITE for CAS and LMA.
3) SG_CODIEREN for KBM, BFS and FAS.

You are done!

If something didn’t work or make sense, please read the step-by-step instructions.
If something is still not working like it should, then there is a problem with your car and/or the seats OR your car and/or seats are not exactly the same as it shows in the Introduction.

Step-by-step instructions

Stuff you will need:
1) Some wire (2 meters/6.5 feet should be enough)
2) 1 small pin for the SZM connector (please read the Tips chapter at the end)
3) Precision flathead screwdriver set (for opening and disassembling the connectors)
4) Torx set and a regular screwdriver
5) NCS Expert and OBD cable for coding, INPA or ISTA is also good for testing but not mandatory
6) Basic knowledge on splicing and connecting wires using your preferred method

Removing the old seat:

1) Tilt the backrest as upwards as it goes and take out the headrest. This makes removal of the seat a lot easier.
Disconnect the negative cable on the battery.
Remove the plastic cover at the front of the seat base to reveal all the connectors.
Disconnect the big yellow connector by pulling the black locking tab away from the connector and pull it out.
Disconnect the small black connector that is attached to the wires going in the big yellow connector.
Disconnect the slightly bigger black connector that is connected under the seat, next to two other smaller connectors.

2) Make sure that no wires or connectors are connected to your old seat anymore. Slide the seat back and remove any plastic covers from the seat rails. Then undo the two torx bolts that hold the seat rails to the floor.
Slide the seat all the way front and undo the two torx bolts at the back of the seat rails.

3) Make sure that your seat is now loose and ready to be removed from the car. The seatbelt buckle will still be attached, but don’t worry, you will remove it once the seat is out.
Cover the door sill with something, because the seat rails are sharp and will likely scratch or break something.
Turn the seat towards you so that the backrest is touching the centre console.
Grab the seat by the rails and try to wiggle it out through the door opening. Take care not to scratch the door panel or anything else. The seat is heavy and a bit niggly to take out, but it will come. Having somebody sit at the backseat and assist might help.

4) Once the seat is out and next to your car, remove the plastic from the bottom side of the seat covering the seatbelt buckle. There is just one clip in the front. Then undo the torx bolt holding the seatbelt buckle to the seat.

Doing the wires:

1) It’s now a good idea to vacuum the carpet to get rid of all the dirt that has accumulated under your old seat.

2) Disassemble the car-side big yellow connector. The black locking thing is held by a small tab, pry it loose and you can remove the yellow part where all the wires connect to.

3) The only wire that you need to run is from the SZM module (that is the button box in the centre console with the heated seats and DSC button) to the comfort seat big yellow connector. It’s good to do it now with the seat out of the way so you can run the wire under the carpet etc.
So, you need to take out the SZM module. For detailed information on how to do that, you will find several videos and DIY instructions online.
In short, pull the shifter leather up and undo the two torx bolts that are revealed. Pop off the iDrive controller and just pull up on the trim, which is held in by just a few clips, starting near the armrest. Once you get it off, disconnect the Menu button connector, wiggle the shifter leather through the hole in the trim and pull the trim towards the back of the car to release it. Then pop off the big trim around the air vents (just clips again), you don’t have to take it off completely. Behind it you will see two Phillips screws holding the climate control panel, undo those and pull the trim off the two clips near the CD slot. Again, don’t have to take it off completely, just away a bit so you have room to pull out the trim around the SZM module. You guessed it, just clips again. You can now take out the SZM module and undo both of the connectors.

4) Disassemble the bigger connector and you can see the numbering for the pins. You need to add a wire to pin 3 (which is supposed to be empty – if it is not, then your car is different than what I described in the Introduction). So find your small connector pin and click it in.
If you are doing one seat at a time like I did, connect both two wires to the pin now, then you don’t have to do it again for the other seat. Route one wire to the driver’s seat and other to the passenger seat. Don’t hurry putting everything back together, let’s continue and test it first.

Installing the new seat:

1) Install the seatbelt buckle on the comfort seat. Try to make sure you don’t twist the seatbelt.

2) Now it’s time to put in the new seat. It will be heavier than the one you took out, so again having somebody to help makes it easier. Use the same techniques that you used for removing the other seat and try to wiggle it in place. Do not bolt it down just yet.

3) Disassemble the comfort seat big yellow connector. You will see that it actually consists of several small black connectors that are marked A-B-C-D (marking their position in the yellow connector, even though they are different shape and cannot be put back incorrectly) and that they also have numbers for the pins.

4) Find pin 2 and attach one of the wires you ran from the SZM module using your preferred wire connecting method.

5) Now have a look at the seat module under the seat. It has a lot of smaller connectors. Disconnect the slightly larger black one that looks like this:




It has a thick brown wire (ground) and a thick red/red-green/red-brown wire (positive) next to it. Remove those wires from this connector (with the precision flathead) and isolate the ends.

6) Now find the same two thick wires from the car-side big yellow connector. Remove those wires and insert them into the black connector where you removed the other two from. If you don’t remember, brown goes below the other wires (these are CAN lines fyi) and red next to brown.

7) You also need to run two short wires from those thick brown and red wires to other seat connectors. From the thick brown wire, run a wire to comfort seat big yellow connector pin 11 and from the thick red wire to pin 3. You can either remove some isolation and connect the wires like that or do it nicely and remove the pins, connect the wires and reinsert the pins.

8) That is now everything done with the wires. Make sure everything is properly isolated, maybe do a little bit of cleaning and then connect everything back up. Make sure all the small black connectors inside the comfort seat big yellow connector sit firmly in place. Double check ALL the connectors in the seat module as well.

9) If you are happy with everything, bolt the seat back to the floor. Get something to drink, wash your hands and bring your computer with the OBD cable. If you have INPA or ISTA, you can now test if the program is able to move the seats. If something is not working, it’s time to check the wiring and the connectors once more.

Coding:

1) Open NCS Expert and choose a profile (File – Load profile), Expert is fine.
2) F1 and enter your VIN code, calculate checksum
3) F3 and select E60 and CAS module
4) Enter FA, calculate checksum again and you should see a list with „attributes“ e.g. all option codes your car has.
5) Now add $456 and $488 to this list and close it, then press BACK.
6) Click on „Process ECU“ and select CAS
7) „Change job“ to „FA_WRITE“ and click on „Execute job“. It needs to show „job active“ and then „job ended“ – if it’s something different, then you didn’t follow the instructions correctly.
8) Click on „Change ECU“ and select LMA
9) „Change job“ to „FA_WRITE“ and click on „Execute job“.
10) Click on „Change ECU“ and select KBM
11) „Change job“ to „SG_CODIEREN“ and click on „Execute job“. It needs to show „coding active“ and then „coding ended“ – if it’s something different, then guess what? Yeah, you messed up.
12) Now repeat the steps 10-11 for modules BFS and FAS.
13) You are done! The seat should now move from the buttons and you should also get „Seat heating distribution“ sub-menu in your iDrive Climate menu.
So either move on to the second seat or put everything back together and proceed another day.

Tips

1) About the SZM connector pin – you can either order something like 61131393724 or if you have any old BMW parts lying around, you can check if maybe you can find the correct pin there. I found some wires that I got when buying new HiFi tweeters, so I just took the female pin from there and it was the correct one. It needs to click in place inside the connector.

2) Do one seat at a time. The first seat will almost definitely take a bit longer, so then for the second seat, you already know what you need to do and it will be a lot quicker. You will also already have the wire from the SZM module in place for the second seat. Your old seat will still work even after coding, so there is no reason why you should definitely do both seats at once.

3) Take your time, have a good look at your connectors and compare them with these instructions. Cars can be different and there might be some differences. If you are unsure of anything, google for other comfort seats retrofit guides and see if it helps you to figure everything out.

4) Some instructions say that you need to add two CAN wires to SZM module and also two wires to B-pillar airbag module. If your car and seats are the same as shown in the Introduction chapter, you don’t have to that.

Good luck!