BMW E90 3-series Seat Swap

[phattyduck]

Currently doing this swap in my '01. Curious if you have any insights on wiring the power for the occupancy sensor (green/yellow strip) to which wire on a F30 seat to make sure the SRS system still fires if a passenger is present. Having trouble finding any BMW wiring diagrams online...

Unless I should just bypass it altogether and close the circuit so the SRS things someone is always sitting there. Not sure of the ramifications of this approach.

I wouldn't trust the BMW occupancy sensor to do anything remotely the same as the early Toyota sensor. I would wire it up as if there was an occupant all the time (and the seatbelt buckled). Not ideal, but probably the safest overall. You'd basically be going back to '96-'00 style airbags on that side of the truck.

-Charlie

 

[Griff12]

Anyone have a F30 wiring diagram by any chance? I'm having a hell of a time finding one and trying to figure out the wiring - even for the pos/neg on the BMW seats. If it matters, the seats came out of a 12-17 328i..

 

[phattyduck]

Anyone have a F30 wiring diagram by any chance? I'm having a hell of a time finding one and trying to figure out the wiring - even for the pos/neg on the BMW seats. If it matters, the seats came out of a 12-17 328i..

TisUI

Get a subscription for one day, get the info you need... I've done the Toyota equivalent when I needed specific wiring diagrams.

-Charlie

 

[Griff12]

A little progress update (sorry for reviving an oldie): I got the passenger F30 seat in my 2001 SR5 after following the info in this and related forums. Took a bit of work getting the feet to line up (and I'm convinced that no two T4R/BMW Seat combo will ever line up exactly the same way). Went to wire up the seats and learned some stuff that might help others down the road..

My truck has a 3-pronged connection under the seat with blue/yellow (hot wire), white/black (ground), and green/yellow (occupancy sensor/SRS activation system as mentioned a few posts ago). Wired hot and ground to the corresponding wires on the F30 seat and no luck. Used a multi-meter to confirm 12V at the passenger seat but still no dice. Hooked F30 seats up to a spare 12v battery I had lying around with some thicker wire and seats powered up no problems. Went back into the truck and rewired to existing hot/ground in truck and still didn't work. My only guess is the thickness of the factory wiring. Appears to be 18-20ga (truck didn't have powered seats) whereas the factory BMW wiring is 16-14ga. So, moving forward - it looks like I'll be trying to find a fused accessory wire somewhere that I can tap into to provide power to the seats.

Again, sorry for digging up an old thread. But, since this seems to be the main one-stop-shop for info on this topic already, I figured I'd document my findings. Curious to hear other peoples thoughts, opinions, etc.

 

[martaigne]

Here’s my current set up. Black interior and F32 seats

And this is how I made the heated pads to work

I used these switches
3 Pin 12V Universal Car Seat Heater Switch- Round High Low Off Control Heated Seat Switch Amazon.com
And a 30 amp relay

Hi, I'm over here perusing this thread to find out how to wire in F32 seat heaters in my LX470 but it looks like the hosting for these images is dead. Anyone have the wiring diagrams for this?

Edit: I found this diagram of the heaters.

Assumptions:

1) As Griff12 mentioned above, the seat heaters are triggered by KCAN signal, as they are not wired independently going into the seat module.
2) The GRAY wire is connected to a temp sensor with automatic shutoff to the heater circuit.
3) Power from switches (assuming correct amperage) can be wired directly to the GREEN and GREEN/VIOLET wires, with BROWN going to ground.
4) This would lose/bypass the temp sensor unless we wire in another circuit to accept the signal and cut the power to the heater circuit.

 

[Griff12]

Little status update:

Finally got around to finishing this project. Mounting the F30 seats with the T4R mounting feet was definitely more annoying than difficult. Ended up accidentally snapping the plastic guide rail on the Driver F30 seat so I had to disassemble and install an aftermarket one off eBay. Not a perfect fit, but I got it working.

As mentioned in my last post, my T4R didn't have power seats so I had to make a circuit to provide power. Ended up wiring up a 30a relay that uses accessory power behind the radio to provide switched power to the seats. All in all, everything works smoothly. I'm not a fan of how skewed the rear outermost feet are on both seats, but they seem secure. I may end up seeing if I can get some custom feet made that line up with the reinforced mounting hole on each of these.

As for the driver seat going to sleep - I just wired up a fog light switch (p/n 00550-35976) that mounts onto the dash. Flip the switch on, make my adjustments, then flip it off. Not perfect by any means, but I'm happy with it.

 

[giogastelum]

If you provide 9v to the INH pin of the seat computer they can stay awake but without memory it depends on the chip is the location of the TJA1054 and TJA1043 pin
https://www.nxp.com/docs/en/data-sheet/TJA1043.pdf
https://www.nxp.com/docs/en/data-sheet/TJA1054.pdf

 

[Griff12]

I wouldn't trust the BMW occupancy sensor to do anything remotely the same as the early Toyota sensor. I would wire it up as if there was an occupant all the time (and the seatbelt buckled). Not ideal, but probably the safest overall. You'd basically be going back to '96-'00 style airbags on that side of the truck.

-Charlie

Just trying to confirm my understanding.. Using the 01-02 SRS EWD, it looks like SRS wire (Y/G) w/ normally-open occupancy sensor switch is wired in series with normally-closed buckle switch. So, for the SRS to be active, Y/G simply must not see ground, right? If I connect Y/G to ground (W/B), my passenger seatbelt light flashes.

In the event of this swap, since I'm not reusing the 3-wire connector on the stock seats, by leaving Y/G, B/Y, and W/B wires all disconnected, the system should think that there is a passenger and their seatbelt is connected, right?

 

[phattyduck]

Just trying to confirm my understanding.. Using the 01-02 SRS EWD, it looks like SRS wire (Y/G) w/ normally-open occupancy sensor switch is wired in series with normally-closed buckle switch. So, for the SRS to be active, Y/G simply must not see ground, right? If I connect Y/G to ground (W/B), my passenger seatbelt light flashes.

In the event of this swap, since I'm not reusing the 3-wire connector on the stock seats, by leaving Y/G, B/Y, and W/B wires all disconnected, the system should think that there is a passenger and their seatbelt is connected, right?

I had to go back through it - there is no mention of turning the airbag on/off or dual stage airbags (passenger cars needed them by '02, I guess SUVs were still exempt?). It does look like the truck will think that the seat is occupied and seatbelt in use if the connector is disconnected... Odd thing though, is the fact that the SRS computer has a connection to that, but doesn't seem to use the signal (there was no connection there on '00 and earlier 4Runners).

-Charlie

 

[nychawk]

Has Anyone Summarized This Thread - F30 Seats into a Gen3

Hello;

New guy here, just purchased my first ever 4Runner, its a 2002/gen3, for long distance travel/overlanding.

I've seen many great ideas, success stories, and challenges for retrofitting the BMW F30 front seats into a gen3 4runner, but has anyone completed their project and documented it?

I've just purchased a gen3 (love it!) and while I had always intended on reupholstering my seats in new leather, I would much prefer doing so to a more comfortable seat like those in the BMW's.

Ideally, I would like to control the seats heating and cooling elements, as well as all motors. If I can have the seat belt light/reminder work, that would be a great plus too.

Thank you in advance,

New Guy...