[75fusca]

Hi there,

I have a 2014 320i with front -but not rear heated seats. During my ED I picked the rear seats heating pads as well as the rear center console switches, so I could do the retrofit for the rear seats.

Please, can anyone having rear heated seats help me with some information?

CONNECTION
I'd like to know how the heating pads are connected. Cannot find any part numbers, but I saw a diagram which seems to show some "boxes" to where the seat heating pads are connected... Is that right?

WIRING
During my factory tour I was told that all F30s have the the full wiring loom, regardless of the options you pick. If that's the case, I assume the wiring is there, just waiting to be connected to the switches and heating pads.

Any pictures of the actual connection below the rear seats would be of great help.

Much appreciated!

Martin

[Dr.Ho]

The seat-heating is a kind of "over-engineered" (and expensive) German Technology.

Beside the mats, cable harness and Switches, you also need 2 modules (PN 61359216468, ~200 € each), placed under the rear-seats, and 2 holders (PN 61359249125, ~ 5€ each), because the Heating itself is activated by the Rear Electronic Module (REM):

The key signals from the Switch S96a/S97a for the heated seats are transmitted to the REM via the LIN-bus. 3 heating-levels can be switched by the switches. The junction box electronics and the REM processes the applicable key signal and outputs according to the selected heating, a temperature-signal as a message on the LIN-bus to the seat heating modules A5/A44 under the rea seats.

Depending on the temperature signal, the seat heater module generates a pulse-width modulated signal (PWM signal) with which the seat-heating E7/E64 is operated.

The seat heating module detects the temperature by a built-in heating-mat temperature sensor E6/E53, regulates and monitors the temperature in accordance to the selected the heating power.

See the PDF-File for further information

[75fusca]

Hi Dr. Ho,

Firstly, I want to thank you very much for your detailed and informative response, that's very generous of you!

If have one more question if you don't mind about the cable harness: Is there a separate cable that I have to buy to connect the switches to the REMs, or they are connected via main harness?

While at the dealership in Munich, the staff couldn't find any description or part number for a cable harness, so I was able to buy only the 2 switches and all the heating elements for the seat.

Once again, thank you so much for your help, much appreciated!

[//M]

Originally Posted by 75fusca

Hi Dr. Ho,

Firstly, I want to thank you very much for your detailed and informative response, that's very generous of you!

If have one more question if you don't mind about the cable harness: Is there a separate cable that I have to buy to connect the switches to the REMs, or they are connected via main harness?

While at the dealership in Munich, the staff couldn't find any description or part number for a cable harness, so I was able to buy only the 2 switches and all the heating elements for the seat.

Once again, thank you so much for your help, much appreciated!

I gotta ask isn't heated front seats $500 and the whole cold weather package with heated steering wheel and rear seats $800... isn't this method a lot more expensive. You did ED which means you most likely ordered it... (Is BMW CA screwing you guys again?)

Anyway if the under cushion harness is there and the harness for the buttons in the center console is there, you are good for wiring. You just need the modules, mats, buttons, and the holder for the module potentially (to do it right).

To explain further the switches send a signal through Lin-bus to Junction Box who forwards it to REM. REM then send the temperature request to the underseat modules. Think of the modules as the electrical controller, they take the Celicus temp request from the REM and control the electricity into the pads to achieve and regulate the temperature.

Key here are the harness's confirm they're there before buying those expensive modules. If they are plug everything in and add the VO code, and code the car (or at minimum Junction box and REM, but just code the whole car) voilà it'll work.

Edit: no extra harness required, but if the switch or under seat harnesses are not there it's going to be more trouble than it's worth. So as long as you have those go for it.

[75fusca]

Originally Posted by tifosielia

I gotta ask isn't heated front seats $500 and the whole cold weather package with heated steering wheel and rear seats $800... isn't this method a lot more expensive. You did ED which means you most likely ordered it... (Is BMW CA screwing you guys again?)

Anyway if the under cushion harness is there and the harness for the buttons in the center console is there, you are good for wiring. You just need the modules, mats, buttons, and the holder for the module potentially (to do it right).

To explain further the switches send a signal through Lin-bus to Junction Box who forwards it to REM. REM then send the temperature request to the underseat modules. Think of the modules as the electrical controller, they take the Celicus temp request from the REM and control the electricity into the pads to achieve and regulate the temperature.

Key here are the harness's confirm they're there before buying those expensive modules. If they are plug everything in and add the VO code, and code the car (or at minimum Junction box and REM, but just code the whole car) voilà it'll work.

Edit: no extra harness required, but if the switch or under seat harnesses are not there it's going to be more trouble than it's worth. So as long as you have those go for it.

Hi there, thank you very much for your information!

Well, yes, I guess I got screwed by BMW Canada: In as much as I insisted, they wouldn't add the rear heated seats to my order.... (No "cold weather package" in Canada, if you can believe it!).

I'll check to see if the wiring is there, under the seat.

Thanks again, much appreciated!

[Arthurrs]

Originally Posted by 75fusca

I'll check to see if the wiring is there, under the seat.

Were you able to verify if the wiring is there? I might be interested in adding this to my car!

[thesull]

75fusca - I am wanting to do this mod to a set of seats I bought. My car currently is heated rear so maybe we can help each other. The rear seats I bought in Coral Red do not have the heating elements. I can provide photos etc for you and maybe you can provide process on how to put the elements in the seats?

Here is a picture of the box you are referencing. I just took this picture and the rear lower seat and up seat appear to connect to this box.



I was trying to remove the rear seats to swap in my new Coral Red seats and noticed that one had a wire the other didn't then started researching. Noticed I had heated rear seats...

[Warrior9504]

Just found this thread on a Google search. I have a 2016 3-wagon and I'm adding the rear heated seats. As an FYI, I found the modules on ebay for under $20. I also found a replacement center console with the heated seat buttons for $99. Bought the heated seat elements and module brackets on ECS tuning for a total of $500. I will get it all installed by my uphostery guy and let you all know how it turns out. Side note, I am assuming that the wire harnesses are present in my car :fingerscrossed:

[E90_XO]

I can't see a post where anyone has confirmed installing the rear seats, nor a thread.

After following the the diagram posted by Dr.Ho and a bit of coding, I managed to install rear heated seats in my F30.

The wiring is not present in these cars from factory, well at least not in the UK.

So you have to make up your own wiring loom, the plugs are available on eBay. In my case I managed to get them, along with all the other parts mentioned, from the donor car the seats came out of.

After wiring you need to update the VO with 496 and code the REM.

Pretty straightforward retrofit if you can source all the parts for a decent price.

[david51]

I did it on my F30
here is the simplified diagram