Active Backrest Retrofit

NoQuarter

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Nov 24, 2017
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Indiana, USA
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Note: This is a copy of my original post ported to this site. There is still a very strong E60 community wanting to upgrade and retrofit, so this seems relevant.

Project:
Active Backrest Retrofit (5 Series)

Active Backrest is an option for the Comfort Seats where the backrest can be set with a Comfort, Normal, and Sport mode

It was only available with option 456 (Comfort Seat) and was not available with 455 (Active Seats - this is the one that massages your bottom)

I have only seen evidence of it exisiting in M5s but if anyone has actually seen it in anything else please let me know.

So what does it do?
Active Backrest monitors the DSC information and automatically adjusts the backrest on the outside of the turn to tighten up and support the driver/passenger during cornering.


The new buttons shown below. I will first do the install without installing the buttons to see that it can be made to work without the expense of the new buttons. I expect it can be controlled completely through the iDrive controller.
ActiveBackRest1.JPG



My seat on the bench. It is back in the car now, just took it out to inspect.
ActiveBackRest0.JPG



Some of the controller connections
ActiveBackRest2.JPG


The exisiting backrest motor that needs to be replaced
ActiveBackRest3.JPG



My test jig. What you see here is 2 motors for 1 seat - left side and right side. I plan to modify the jig to mount the other 2 motors to represnt both driver and passenger seats during testing
ActiveBackRest4.JPG



The plan:
1) Create the cable harnesses for the seat
2) Create or update the harness from the car
3) Connect Jig to car - code the car - test jig operation during a drive
4) Remove seats again. Remove existing motor from seat. Install 2 new motors per seat with new wire harness. Install seats

I will consider making additional harnesses in the process that I will make available to purchase if it looks like there is interest.
The parts for this retrofit cost about $900USD and I can provide the retrofit harness (assuming I get all this to work!).

I will wait before I am ready to declare the price of the retrofit harness until it is done. Each retrofit kit requires ~100 connections to be made depending on the availability of compatible plugs to mate with existing plugs. If I can't find a mate then I will have to remove existing plugs and replace them also.

Not sure how this retrofit $ compares to the original option price but if you like your existing seats this is better than swapping out the whole seat for M5 seats.

**more to follow when I can work on porting over the original pics and text
 
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derekgates

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Feb 23, 2018
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Wow! This is really cool! I don't have a 5 series, but this seems like an awesome mod to have on your car. Reminds me of Mercedes E class with the bolsters that inflate/deflate during spirited driving.
 
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doublespaces

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Oct 18, 2016
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So, can this be done in a non E60?

Tell me more about the seat massager, sounds like a good retrofit for the passenger side, get things warmed up in advance.
 

NoQuarter

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Nov 24, 2017
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So, can this be done in a non E60?

Tell me more about the seat massager, sounds like a good retrofit for the passenger side, get things warmed up in advance.

Ahhh, you want to upgrade to the "Date Prep 1000" model?

The backrest controller is pretty self contained. The connection to the car is power and PT-Can only. So it just comes down to if the motorized side bolsters and seat back in another model will accommodate the 2 motor upgrade.

At the time when I did this a couple years ago, I couldn't get the menu in the CCC to display without installing the button. Perhaps that can be revisited again, otherwise you would need to deal with where you would install the backrest button.

The butt massager is called "Active Seat" I think. I have it in my X5. It is great for long road trips where there are 2 air bags (similar to how the lumbar system works) right where you sit and they slowly alternate left cheek/right cheek to relieve pressure. It works surprisingly well.
 

doublespaces

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Ahhh, you want to upgrade to the "Date Prep 1000" model?

The backrest controller is pretty self contained. The connection to the car is power and PT-Can only. So it just comes down to if the motorized side bolsters and seat back in another model will accommodate the 2 motor upgrade.

At the time when I did this a couple years ago, I couldn't get the menu in the CCC to display without installing the button. Perhaps that can be revisited again, otherwise you would need to deal with where you would install the backrest button.

The butt massager is called "Active Seat" I think. I have it in my X5. It is great for long road trips where there are 2 air bags (similar to how the lumbar system works) right where you sit and they slowly alternate left cheek/right cheek to relieve pressure. It works surprisingly well.

When you did this, I assume you had an E60 as well?

These are they types of things I think about doing when I see that unused edc button on the m3 console.
 

NoQuarter

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I just did a quick look on realoem. It doesn't look like the 3 series came with electric side bolsters at all.

If that is the case, I imagine this would be very difficult to pull off on a 3 series.
 

doublespaces

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So did you ever finish this on your car? Also if the seats swapped over, what exactly would be required? If its on the PT CAN I assume it takes steering angle sensor along with wheel speed?
 

NoQuarter

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It has been working perfectly for 6 years.
The retrofit coding was pretty easy. Add 4MF to the VO and default expert code BGM, CAPPL, and KOMBI.

Later I updated the software on the actual backrest module and they responded even faster to turning forces.

The backrests use the PT_CAN to get data from the DSC, steering angle, etc then each side responds independently based on the rate of turn and speed. So a mild turn and the bolster moves a small amount. The more aggressive the turn , the tighter the bolster becomes.

it is a practical, fun upgrade and the surprise from passengers never gets old.

I don't have any experience with 3 series seats so I don't know about hings like mounting holes, seat dimensions, etc.

iDrive display
ActiveBackRest13.JPG



This is the side of the seat showing how the bolster is attached to the motor with the hog-rings
ActiveBackRest15.JPG

This is the original motor mounting rivets that need to be drilled out in order to install the new motor

photo16.JPG
 

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doublespaces

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Those photos are really tiny for some reason. I don't know what the BGM or CAPPL modules are/do or if equivalents exist in the E90. Maybe I'll investigate it sometime. Very cool.
 

NoQuarter

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fixed some images.

Also, A great contributor in the original forum, BLooD, posted this info about getting the menu to display. I assume he meant without the need to install the button so this would be a great help to someone who does not want to custom install the switch into a non-5 series.

"Just so your know ALBV_TOGGLE_APP is the function in CAPPL.
If you enable MDRIVE and MDRIVE_ALBV in CAPPL this should give you the seat adjustment menu."

I did have these settings at the time and it did not display in the iDrive screen but perhaps there is still some effort to be made in making it work without the switch.

-------------------------

I took these photos a couple years later when I swapped leather. Here you can see the motors installed and under the seat bottom is the module with the 2 green plugs and the routing of the custom harness I made.

ActiveBackRest16.jpg


Close up of the seat bottom
ActiveBackRest17.jpg
 
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doublespaces

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I did a quick search for someone trying to swap E60 seats into an E9x. But I think I'd have to look at 6 series seats because they made that with a convertible option. I have not seen an E64 with active headrest however, not in my limited search. But I read reports that say M6 seats fit in the E9X, so that is somewhat promising.

I suppose for now, the E60 guys will just keep this feature to themselves :)
 

JuniorB

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May 9, 2017
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Great stuff! I swapped a set of comfort seats in my e60,what a difference. I looked into activating the bolsters during sportmode. There isn't much info out the for this, so what I've found out is there is an extra plug that is to the seat module to the control buttons. Im going to assume this is for cars that have sport mode. The active part looked to require the m5 buttons and facia. I figured it would of been easier if the whole kit was to be purchased if this was affordable, at the minimum, the sport harness would be needed and more readily available if they wanted the sport feel. I also found that comfort seating is pnp if you already have full power and heat. I've taken apart the full power seats and found that the motors are compatible with e90 motors!and wouldn't see why the whole seat couldn't be used.
 

Rob09msport

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I just did a quick look on realoem. It doesn't look like the 3 series came with electric side bolsters at all.

If that is the case, I imagine this would be very difficult to pull off on a 3 series.
I have electric side bolsters on my 09 it m sport with side bolsters on back ,wing that extends on front and two diff bladders in the backrest
 
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Rob09msport

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Will try see if can pull out connector when i get home
 

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