Retrofitting Heated Seats in an E89

[ProfCJJ]

Hi all

I've had my E89 for over 3 years now and its still a joy to drive it (from what I remember as during lock-down its been hibernating under a cover!).

The one thing I always miss on the E89 I bought (used) is heated seats. My E89 has quite a lot of bells and whistles and the one thing I really would like in winter is the heated seats - I waited a while when I was looking buy but when this one came along at the right price I had to buy it - sadly although it has comfy sport seats it doesn't have heated/electrically operated seats.

I've been doing some digging re retrofitting and the following is what I think the state of play is re retrofitting:

- In my 2011 E89 I should not expect to find the wiring already present - so I will most probably need to fit a wiring loom
- Apart from the wiring loom the driver's and passenger seats each need a control box attached underneath (still zeroing in on the actual details)
- Of course I will need a new bank of switches that include the two heated seat switches (in my case I have the PDC switch as well as roof open and close)

I am not sure of the following:

- there is no retrofit kit available? (True?)
- there is no need for coding after fitting the heated seats kit? (True?) The wiring seems to need the K-bus though - so this must be wired in?
- Its not clear if there are seats/ wiring from another BME model that are a direct swap/fit?

I would be looking at getting a retrofit loom that was "close" to what I needed for another BMW model, using "generic" heating pads to fit into my existing seats - modifying the kit to use the BMW heated seat switches for the "OEM" look.

I am OK with most of the above but not sure on the bit using the BMW switches as I am unsure of how they operate at this stage.

So as you can see, still not there yet but a "work on progress".

If anyone has any pointers, links or knowhow I would gratefully receive it

Best

 

[Smartbear]

This should help
https://z4-forum.com/forum/viewtopic.php?f=23&t=92671&p=1367610#p1367610
Rob

 

[ProfCJJ]

This should help
https://z4-forum.com/forum/viewtopic.php?f=23&t=92671&p=1367610#p1367610
Rob

Thanks - I did see that. The issue is that these things get compounded with the inclusion of memory/ electric seating - so its sometimes hard to disentangle the wheat from the chaff. As I will be keeping my non-electric seats I need to figure out which of the connections are relevant to the heated seats circuitry and which are not.

I will certainly update this thread with any info that I find which might help anyone else.

Cheers

 

[flybobbie]

I wonder why with cars that they didn't just pipe some hot air from the heater into the seats.
It's shame that a simple heat pad for £10 couldn't be fitted into the seat.
If the seat is removed would there be access to the space between foam and leather to tuck a pad in.
Might take my seat out and have a look.
I love the hot air vent the one just above my left knee, that heats my key ring to burning temperature.

 

[Smartbear]

I wonder why with cars that they didn't just pipe some hot air from the heater into the seats.
It's shame that a simple heat pad for £10 couldn't be fitted into the seat.
If the seat is removed would there be access to the space between foam and leather to tuck a pad in.
Might take my seat out and have a look.
I love the hot air vent the one just above my left knee, that heats my key ring to burning temperature.

That vent burns my knee, considering putting some foam in it to calm it down a bit.
Rob

 

[ProfCJJ]

Just to add to this thread as I go along, I have so far discovered the following - for fitting heated seats to a car with manual/ unheated M-Sport seats:

1. I need two heated-seat-modules 6926435 (known as A186a and A187a in the cct diagrams)



2. I need to check if I have wiring in place but I doubt it - I will need to run power, ground and control cables from each seat to the fuse box.

3. I will (obviously) need to change the switches to include heated seat switches part 61319146645 (in my case as I have the PDC fitted).



4. I will need a number of connectors and cables to fit to each seat module and for behind fuse box.

Two of these:


and a few others (still looking for part numbers).



5. I will need to code to allow the Junction Box to "know" the heated seats are fitted (as this uses PWM and there is no moving/memory seats involved, no other programming is required) - will need to use INPA for this (I have Carly but I don't think it will code this way).