DIY Heated Seats Retrofit

DIY: Non-Heated to Heated Seat Retrofit!! Lots of Pics!!!

Alright it's finally put to rest Heated Seat Retrofit. So here goes my DIY with lots of picturesdocumenting my process, materials/tools used and needed.

Parts Needed:

1. Heat Seat Elements Baffles - I purchased for $100 from a fellow fanatic2. Heated Seat Accessory Panel with the Heated Seat buttons - I got lucky on this one of ebay(I got the sunglasses console climate control version with the climate control unit, theaccessory panel, and ashtray for ~ $803. Wiring, Fuses, Butt-Connectors/Quick disconnects, Zip Ties and various OEM BMW specficconnectors/pinouts - Already had so $0 for me!4. An Upholstry Shop capable of doing car seats, I found one 5 minutes from me and chargedme $150 per seat - $300 total

So my total cost was ~ $480

Here are some pictures:

DIY: Non-Heated to Heated Seat Retrofit!! Lots of Pics!!! - E46Fanatics http://forum.e46fanatics.com/showthread.php?t=341242

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Tools Needed:


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Torque WrenchT-15 SocketT-40 SocketT-45 Socket10MM hex socket17MM hex socketPhilips Head ScrewdriverFlatHeadNeedle Nose PliersCrimping Tool

Allright lets get started:

Step 1: Disconnect your battery

Step 2: Remove/Unplug your seats from the car

Step 3: Once the seats are removed, nows the fun part! Dismantling your non-heated seatbaffles. It's actually fairly easy start by taking off the backrest portion this is only held on by 2T-40 bolts you must pull back the leather/leatherette to gain access to them. Once these 2bolts are removed the backrest will come free with a little bt of strength.


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02-25-2006, 05:50 PM #2

Ivegotissues666OEM ///Member Join Date: Jul 2004Location: Boston, MAPosts: 990My Ride: 01' VW Golf 1.8TView My Garage

Flip the seat upside down and you will notice I think they are called HOG RINGS. Well you canuse a pair of pliers to undo the ring there are 2 - 3 on each side left nright at the back of theseat.

Now you have to remove these other 2 T-15 bolts attached to these plastic covering. This willi t ll ff th b tt t b ffl It i h ld b l l ti ldi / li


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give you access to pull off the bottom seat baffle. It is held on by a long plastic molding/clipand can be easily popped up with either your fingers or a flathead screwdriver. Just work yourway pulling up that molding and you will eventally hve the bottom part of your seat free.(Note: On the passenger side bottom protin of the seat, there is a sensor that has to do withthe airbag. It is part of the seat and shld be dealt with delicately.)


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Step 4: Take your non-heated seat baffles to an upholstry shop and have them put the heatedelements into them. In the meantime let's work on your wiring harness considering you wo'tbe able to drive with no seats. haha

Step 5: I opted not to puchase the OEM BMW retofit kit simple because I wanted a challengefirst off, and second I wasn't going to pay ~ $300 for a wiring harness and button panel that Icould easily make and obtain. First lets look at Heated Seat Retrofit PDF manual, it givesdetailed information on the wirig harness. I read through i and simplified what the harness isall about here is the way I saw it as:

To Passenger seat Side:

B1 - Seat Heating On (GN/YE) - Plug X279 Pin 25B2 - Ground (BR) - Plug X279 Pin 24B3 - Temperature (WT/BL) - Plug X279 Pin 23B4 - Ground (BR) - Under Pass Side Skirt (B2 <---> B4)

To Driver seat Side:

A1 - Seat Heating On (GN/VI) - Plug X275 Pin 25A2 - Ground (BR) - Plug X275 Pin 24A3 - Temperature (WT/GN) - Plug X275 Pin 23A4 - Ground (BR) - Under Driver Side Skirt (A2 <---> A4)

To Console Switch:

Passenger Side:

B1.1 - Seat Heating On (GN/YE) - X1869 Pin 1 (B1 <---> B1.1)B3.1 - Temperature (WT/BL) - X1869 Pin 20 (B3 <---> B3.1)

Driver Side:

A1.1 - Seat Heating On (GN/VI) - X1869 Pin 13 (A1 <---> A1.1)A3.1 - Temperature (WT/GN) - X1869 Pin 21 (A3 <---> A3.1)

To Fuse Panel:

C - K-bus (WT/RD/YE) Fuse Box Joint Connector X10116 (Trigger/Accessory Wire) Pin 23 -Console SwitchD - Terminal 30 (RD/VI) Fuse Holder A46 slot No. F42 (30 amp) Pin 7 - Console SwitchE - Terminal R (VI/BL) Fuse Holder A47 slot No. F12 (7.5 amp) Pin 22 - on Console Switch

As you can see I simpilfied it or at least to me it seems that way. Anyways lets start wiring.

Step 6: Removing Glove Box and Driver side steering column panel, both are held in byphilips head screws. Now lets start making your wiring harness. Starting with the drivers sideyou need 3 wires (1 for Ground, 1 for Temperature, and 1 for Power (Heating On function) Ididnt have the multicolored wires like BMW so I just made do with what I had. I tried to matchthe wire colors up as best I could for instance if the OEM wire was White/Green I would makemy wire White etc..


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Drivers Side:

16 Gauge wire: (The Green Wire should have been 14 Guage but I didn't have any availableand the 16 Gauge should be fine)

White - 9 ft (Temperature Wire) - Pin 23 at the Drivers Seat PlugGreen - 9 ft (Heating On Wire) - Pin 25 at the Drivers Seat Plug

Brown - 3 ft (Ground Wire) - Pin 24 at the Drivers Seat Plug


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02-25-2006, 05:51 PM #3


I routed the wires under the foot trims and behind the steering column panel to the conslearea where the accessory panel with the heated seat buttons will be located. The Ground wireis connected in a Stock Grounding point underneath the carpet. You need to pull the carpet upa little bit in order to access it and there are a few empty slots (Note: You will need a OEM pinconnector to get it to secure correctly you will need to crimp or solder this connector to theBrown wire in order to supply a Ground connection to the seat)


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Passengers Side:

It is the same method as the Drivers side in terms of routing the wires. The Grounding pointwill be bend the carpet, and youwill rute the wires behind the fuse panel to the console areawhere the heated seat buttons are located. The wire colors I used for the Passenger side are:

Blue - 9 ft (Temperature Wire) - Pin 23 at the Passengers Seat PlugYellow - 9 ft (Heating On Wire) - Pin 25 at the Passengers Seat Plug


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Brown - 3 ft (Ground Wire) - Pin 24 at the Passengers Seat Plug

Fuse Panel:

The fuse panel is suspended by 2 plastic knobs, you must open the fuse panel and then pushthe fuse panel up in order to release the panel from it's mounting points. Once this isaccomplished the fuse panel will drop down and give you more room to access and playaround with.

Now running wires into the fuse panel is a little tricky yet still doable. You will need anadditional 3 wires plus some OEM BMW connectors:

1 - 12 Gauge Wire ~ 7 ft - Red (Run this wire from fuse #42 - 30 AMP Fuse to the centerconsole area, this s what supplies most of your power to your heated seats


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2 - 16 Gauge Wires ~ 7 ft each- Red/Yellow (Run this wire from the comb connector that has all the Red/White/Yellow Wireson the fuse panel to the center console area. This is basically turn on Lead for the HeatedSeats)

02-25-2006, 05:52 PM #4

Ivegotissues666OEM ///Member

- Blue (Run this wire from fuse #12 - 7.5 AMP Fuse to the center console area)


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/// Join Date: Jul 2004Location: Boston, MAPosts: 990My Ride: 01' VW Golf 1.8TView My Garage

Step 7:

Now working at the center console area with the 23 pin plug connector. You just ran 7 wiresto the console area. Those being:

1. White2. Green3. Blue4. Yellow

5. Red6. Red/Yellow7. Blue


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These connect to the 23 pin plug at the center console area in the following order. You mustcrimp or solder the connections and put them into the 23 pin plug connector.


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1. White - Pin 212. Green - Pin 133. Blue - Pin 204. Yellow - Pin 1

5. Red - Pin 76. Red/Yellow - Pin 237. Blue - Pin 22


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Note: There is also a little 3 pin connector on the backside of the accessory panel you can plugn your DSC (4 pin) connector to this the new panel uses one less wire which I think is 12vConstant because it is now being supplied from the fuse panel.

Step 8:

Now go back to other the Drivers and Passengers side harness that are found underneath theseats. You must unlock the connectors first. Once you have done this now locate on the:

Drivers Side: Pins 23-25 Crimp or solder the pinout connectors as follows:

Pin 23 - WhitePin 24 - BrownPin 25 - Green


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02-25-2006, 05:53 PM #5


Passenger Side: Pins 23-25 Crimp or solder the pinout connectors as follows:

Pin 23 - BluePin 24 - BrownPin 25 - Yellow

Now lastly resecure the connectors and you are done with the wiring portion.

Step 9:

Pick up your seats from the Upholstry shop if you don't have them already and begin toreassemble your seats. Installation is the reverse of removal only difference is that you mustswap out the seat belts that come with the additional wiring for heated and power seats. Usingyour T-45 socket undo the seatbealt and trace the wiring undoing the plastic clips that securethe wiring harness and remove the old connector. Installation of the new seatbelt and wirngharness is the reverse of the process youjust used to remove the old one. Also there is a 2-3pin male and female connector that connect both the backrest of the seat and the bottom partof the seat make sure it is connected or else the heating elements will not work.


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02-25-2006, 05:53 PM #6



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Step 10:

Once the seats are reassembled, put them back into your car and bolt them down torquingeverything to spec. Plug in the 25 pin female plug connector under the seats to the new malewiring harness attached to the seats.

Now working at the center console area plug in the 23 pin plug connector to the back of theaccessory panel and the also the 4 pin plug connector if applicable.

Step 11:

Reconnect your battery, and start your car. And.... there you have it, heated seats!!! Push thebutton once and all 3 lights on the button should light up. Push it a second time and only 2will light up, this is part of the temperature setting to set at a certain temperature.


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Once Everything is working correctly reinstall everything (Foot Sills, Covers, GolveBoxeverything is reverse of removal) Just a quick note: the wire colors I used are for myreference only because those are the colors I chose to use they are not the BMW OEM Wirecolors as found in the retrofit PDF file. Also if anyone wants the retrofit pdf file just PM mewith your email and I will gladly send it to you, unless someone would be kind enough to hostit for me and everyone on the forum.

Well I have to say this retrofit wasn't as bad as I thought it would be. I'd say it took me 6hours total from running the wiring neatly to reassembling the seats, besides the couple daysof downtime of waiting for my seats at the Upholstry shop. I never ran into any issues withwiring snce I've wired my (Foglights, Angel Eyes, and Footwell Lightng, Heated SteeringWheel) driecty from the fuse panel so I really didn't expect to have an issue with this.

I hope this write up comes in handy for those who want to attempt this or are in the processof doing it. I so far after only one day of having heated seats hae not one regret about doingthis retrofit and yet the heated seats compliment my Heated Steerng wheel as well.


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DIY Heated Seats Retrofit