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Subject: Adding MEMORY to your passenger seat (46 photos) Author: ripp222 : member since January, 2006 : 434 posts Posted on: 2009-03-06 21:56:47

Below are the details and history behind adding memory to your passenger seat. This was done on a LHD vehicle, so some part numbers would be different for a RHD.

A bit of History:
I always found the rear seat controls intriguing. Last year I purchased the harness that resides in the rear armrest in order to more easily add remote rear sunblind control (see my signature). With the remainder of the harness laying around I wondered if there was a way to move the passenger seat memory button to the passenger door panel. Looking in WDS I was surprised to find out that there is a wiring diagram for just this set-up! In fact the controls and memory button in the rear armrest are referred to as the "remote" seat control - which leads one to believe the "main" seat controls would reside on the seat itself - the same as the driver's seat.

The only complication is that I have Sport Contour seats, not the Comfort seats which BMW fitted when you have passenger seat memory. Perhaps BMW intended to offer the Sport Contour seat w/ memory, as there is a separate diagram for "passenger's thigh support with memory". Needless to say I couldn't find a passenger seat harness w/ memory for a Sport Contour seat, so some wire harness mods were necessary.

On to the retrofit...

Required Parts:
61-12-6-900-754 Wiring Co-Driver's Side
61-31-6-910-718 Switch, Seat Adjusting Front Right w/ memory
61-31-8-360-465 Button for Front Seat Adj w/ Memory
61-31-8-360-286 Right Front Backrest Adjustment Button
61-31-8-352-160 Seat Memory Switch
61-12-8-362-648 Center Arm Rest Wiring Harness: for the 6 pin Memory Switch connector and wiring to Passenger Door Module
6 seat motors w/ memory for Comfort Seat (7 motors for Sport Contour)
Friction Tape (3M Friction Tape, item 39255, from Lowe’s)

I didn't list out the motor part numbers as they run around $175 each, making the mod overly expensive. I purchased them all used from Ebay (thanks Scubba Steve!). Another option is to purchase a used driver's seat and take the motors from it. Technically you may not need the physical motor, just the black control boxes which are mounted to them. For example, I found it very difficult to remove the upper seat back angle motor and just soldered the black control box to the 2 existing wires - and this worked!

Additional Parts for Sport Contour seat:
61-13-1-383-776 Socket Terminal MQS, .35 to .50 mm2 (x4)
Crimping tool for Socket Terminals (I use the Sargent 1028CT)
Motor connector w/ wires and thigh support switch connector w/ wires (I used pieces from a driver's seat harness)
Friction Tape (3M Friction Tape, item 39255, from Lowe’s)


PHASE 1 - SEAT MODIFICATION
Here's the layout of the new seat wire harness, new passenger seat switch box and used seat motors. This needs to be installed into my existing passenger seat. Note: not all connections will be used depending on what options you have. The wire harness supports 4-way lumbar, heated seats, the vanity mirror in the headrest and active seat bladders - basically every possible feature on a Comfort seat!


Remove seat from vehicle, remove plastic zip tie, plastic trim and disconnect seat belt tensioner & contact connections.


Remove wire harness from rubber band.

Remove trim on left and right side. Note: With left side removed the seat can tilt back further.


I removed my right trim entirely as I was replacing it. Here's a shot showing the existing wire harness connections.


Remove 2 Torx bolts and tilt the seat entirely back and now you can see the relatively simple layout in between the seat rails.


Remove 2 long bolts and motor. Note the black control box on the replacement motor w/ memory.


Remove air pump, 2 long bolts and motor. Note the black control box on the replacement motor w/ memory. Also remove the metal bracket on the gear box and re-install the nut.


The next 2 motors have very restricted access to their 4 mounting screws. Note the one that I've loosed.


As such I decided to disconnect the entire metal bracket which houses them. This required removing the thigh support piece, cutting 3 hog rings and pulling the leather back enough to expose the 2 mounting screws on the top side.


With the brackets loose, remove 4 short screws for each motor. Do NOT install motors w/ memory yet if you have Sport Contour seats.


The thigh extention motor is also difficult to remove. Again I removed the metal support bracket by removing it's screws. Note the screw for the previous bracket shown by the Red arrow.


With the thigh extention metal support bracket loose, you can remove the 3 machine screws and then remove the motor and gear box assembly.


I did not have a thigh extension motor w/ memory... so I used a spare headrest motor w/ memory. The next 5 photos show the conversion.

Extra headrest motor w/ memory and original thigh extension motor and gear box assembly.


Swapping the motors leaves the black memory control box NOT in the correct location.


So the memory control box was removed.


A new mounting hole was found under the label and the black memory control box installed there.


The old mounting hole was covered w/ aluminum tape.


Install motor w/ memory using 3 machine screws.


Now you can install the 2 previous motors w/ memory.
Remove seat back trim, unfasten leather, cut wire ties and pull old harness out. Pull new harness through.


Overview of seat back and cut wire ties.


There are 2 "C" clips which appear to secure the upper seat back angle motor to the frame, the top one has decent clearance.


The bottom "C" clip has poor clearance, so I decided to leave the motor attached and just add the black control box.


First remove the black control box from the replacement motor.


Re-assemble black control box.


Cut the old harness and solder the 2 wires from the black control box to the motor, then zip tie to one spring wire.


The headrest motor is also difficult to remove, though I found a flexible shaft screwdriver was able to remove the 2 mounting screws for the motor.


Here is the original headrest motor and headrest motor w/ memory.


Finish installing new seat wire harness. The thigh support motor however doesn't have a connection to the Seat Switch, so a portion of a used driver's seat wire harness were used. Here is the connection for the motor, 3 wires (power, ground & communication)


Here is the connection for the thigh support switch, 3 wires.


Cutting open the new seat harness, locate the Power and Ground bundles and solder the 2 respective thigh support motor wires from the custom harness. Wrap harness w/ friction tape.


Route the communication wire (blue in photo) to the Seat Switch connector, pin 16
Route the thigh support switch wires (all 3) to the Seat Switch connector, pins 5, 6 & 26
This is where I use the 4 sockets and crimp them to the 4 wires.


Connect all motors, make lumbar connections, make heated seat connections, re-install all zip ties, etc. Here is a shot of the new layout between the seat rails (I did add the Active Seat bladders while I had the seat out, so mine is a bit more busy!). The arrows point out the black control boxes for memory.


PHASE 2 - MEMORY SWITCH INSTALLATION

Remove door panel and note existing hole and cutout for passenger memory switch!


Cut out piece for memory switch.


I planned to turn all the buttons 180 degrees and them mount the memory switch upside down so that it would mirror the driver's switch. The buttons are keyed so you can't flip them. As a result I just swapped #1 and #3 so the numerical order would be the same.


Install passenger memory switch.


The switch needs 6 wires total, 4 going to the passenger door module and 2 for illumination. The 4 going to the door module go to PINS 2, 5, 13, 18. Note: my door module is P/N 61-35-6-904-247 and I'm not sure if all of them support passenger memory!


I tapped into the window switch illumination wires to drive the 2 wires for the memory switch. Then all 6 were soldered to the piece I cut from the rear armrest wire harness.


The wire routing followed the existing harness for the most part.


Assemble door panel back together.


PHASE 3 - P-BUS INSTALLATION IN CAR HARNESS

This phase was very short for me as the car harness leading to the seat harness already had the P-Bus wire installed! Look for a Blue w/ Red stripe wire going to pin 15.


PHASE 4 - CODING

I don't have a GT1 or SSS so I used INPA to check the status of the modules which the General Module (GM3) sees. Note my GM3 shows the "SM BF" as "NO" for being coded to the car.


Looking at the identification page shows the new module exists for passenger seat memory, "6910718" with a manufacture week of 39 in 2007.


Now run NCSExpert, read the GM3, open the .TRC file in Notepad and I found "PM_SITZMEMORY_BEIFAHRER" set as "nicht-aktiv".


Change to "aktiv" and re-code module.


Close NCSExpert, run INPA and check the 2 previous screens. Now it shows coding is complete for at least the GM3 module...




I'm not sure if the Vehicle Order (GM/SA/VN) needs to be updated, but the seat sure works!

And for the final result...
9 MB Movie

My ride...

04/1999 build 740i, Anthracite w/ Black Montana Leather
MODS...
0-006-783 Clear Indicator Set w/ 6-904-837 & 838 Clear Tail Lights
9-115-032 MKIV Computer w/ 6-923-879 Widescreen Monitor
1-422-379 Vavona Wood / Leather Shift Lever
2-265-542 Wood & Chrome black headliner handles
6-964-398 New Gen BM53 Radio and 6-906-082 Antenna Amp
0-303-079 OEM reversing camera w/ 0-303-083 Video switchbox
Rear Seat Sunblind Control
Automatic Rear Headrests
Active Seats
Passenger Seat Memory

• Adding MEMORY to your passenger seat (46 photos) (pic) (url) - ripp222 2009-03-06 21:56:47 (15094 views)
  • Thanks for all the great feedback!! Makes it worth the time to post the mod! (nt) - ripp222 2009-03-08 13:32:11 (484 views)
    • You bet. This is the bible for anyone doing this upgrade. Thank you! (nt) - Shled℠ 2011-08-26 23:03:25 (155 views)
  • Absolutely remarkable - most detailed (and scary) mod I've ever seen (nt) - kewashi 2009-03-07 18:48:28 (488 views)
  • Today proved me wrong, I need this mod. - CarlT 2009-03-07 15:16:09 (492 views)
  • Now I know why it is not there to begin with.............. (nt) - TxDarth 2009-03-07 11:19:49 (505 views)
    • Ha (nt) - Ed 2009-03-07 11:26:55 (442 views)
  • I'd like to nominate you for most informative and in depth DIY of the year! - Lexicon 740iL 2009-03-07 11:13:10 (431 views)
  • Great mod and writeup! (nt) - titanium740il 2009-03-07 06:08:04 (465 views)
  • Remarkable work. Well done! (nt) - RobinK 2009-03-07 05:22:50 (511 views)
  • Wow... I was wishing for this mod, but not anymore... (nt) - CarlT 2009-03-07 03:31:44 (532 views)
  • Just plain and simple Awesome!! great job! Now this is modding!! (nt) - Edwin™ 2009-03-07 02:33:46 (546 views)
  • wow. impressive (nt) - sdmike 2009-03-07 02:13:34 (537 views)
  • Awesome! Simply Awesome. (nt) - farnarkler 2009-03-07 01:12:19 (417 views)
  • Well done. I admire your sense of detail. Excellent write up. (nt) - rg0115 2009-03-06 23:43:55 (614 views)
  • Excellent write up!!! E38.org for sure!! Unreal job!!!!!!!!!! (nt) - zapperjoe 2009-03-06 23:20:20 (501 views)
  • Absolute Genius.....Great Job...heck and I thought it was just the me button.GJ! (nt) - snitch740i 2009-03-06 22:29:17 (460 views)
    • just when ur in Awe of his detail he tops it off with Coding - snitch740i 2009-03-07 02:45:19 (464 views)