Heated seat retrofit with pictures

[aimtimes100]

im confused,it looked like a simply plug and play DIY and then got a lot more complicated.few questions.1 im assuming the switch for the heated seats isnt already there correct?2 on a scale of 1-10 how easy is it to pull out the carpet.3.is unbolting it necessary?sliding the seat back all the way wont get the job done?4.this installment of heating elements and other wiring necessary or did u just go above and beyond for your satisfaction

[nigwhyrito]

Hi Aimtimes to answer your questions it all depends on you.
1. If the oem switch for heated seats is not in your X. You will have to buy it. Possibly ebay or parted out X like I did. Appears to be standard on 4.6's and 4.8's
2. scale of pulling out the carpet. 2. 2 being very easy.
3.Unbolting the seat is neccessary. They hid \ziptied the wire directly under the rear area of the front seat but they zip tied to the metal in the front. I pulled center console out because alot of threads on here said you had to. "After doing this I feel you still have to lift the center console up in the back because you still have to fish the rear heat seat wires back to where the switches mount." " sliding the seat wont get the job done" Nope look at the back on the ground of your front seat. You see the the airvent.. under it is a hump. That hump in the carpet under the airvent is where the wire is ziptied to the frame. Unbolting is neccesarry to gain clearance and to safely cut the ziptie.
4. HEHE both.. the heating elements I used are older from my kia sorento before I crashed it. It used the older 2 wire method. Most heat elements on the market nowadays are 3 wire design. mine werent. So Ihad to modify the circuit to allow 3 wire design ( thermistor). I wanted as oem look as possible. that meant wiring, connectors, switches.
Most aftermarket heat elements you buy come with there own non oem switch like a rocker. if you do buy aftermarket and want to use oem switchs make sure you buy dual stage heating elements. Mine were single stage thats why I had to modify the circuit. ( BMW uses 2 different temps hi,med and off for the heating elements) kia only used 1 hot and off.
If you want plug and play I think its $400 to $1,000 usd for used or new rear seat covers with the elements in it. Because BMW sews their elemements into the leather.
Any more questions feel free to ask.

my total= $100 for all the bmw connectors from stealership. Now we know part numbers about $24 - $50 bucks online.

oem switches - ebay possibly $25 to $50 bucks
mine were parted out - got 5 parts for 100 bucks
1 oem relay, 2 rear seat lights,2 rear switches, 1 cig lighter cover.

oem relay - $5 to $10 bucks online

hogring pliers and hog rings - $25 off ebay.

heat elements I already had but originally $100 ebay about $120 to $150

new diagonal pliers/cutters $20 bucks at home depot- mine sucked had toget new ones made a whole lot of difference.

2 thermistors to make dual stage elements - $6.64

1 trip to stealer to reset the airbag light..- forgot to fully disconnect the battery terminal..just did the big ground wire.. $75 effing bucks. DOH.

time and effort really 2 weekends 1 weekend to rip front seats out and center console out and search for wires but since I showed basic location could be done in 4 hours tops
1 weekend to pull out rear seats and install elements.. uhm first time.. now i know how to do it. possibly 1 whole day.
2 weeks of waiting on bmw connectors. 1 week of waiting in thermistors
1 week waiting for the parts to ship.

so its really up to you. But like i said i am now looking into ways of cooling seats rear and front. like ac vents and thermoelectric. I may even use thermo electric sample to have heated and cooled cup holders Thermoelectric Device Demonstration Peltier Effect - Cooling - YouTube. heheh.

[cooluserid]

Great thread. I have three questions:

1. Where did you get matching OEM connectors? What are the part numbers?
2. Your test with potentiometer showed >6kOhm thermistor resistance to start heating. Was it with high or low settings (two or one LED on the control switch)? Did you measure the other one?
3. Why did you choose 50K and 10Kor 30K?

50KOhm thermistor will be at 6KOhm at 75C or 167F
30KOhm thermistor will be at 6KOhm at 60C or 140F
10KOhm thermistor will be at 6KOhm at 38C or 100F

[nigwhyrito]

Hi cool
okay answers
1. part numbers and parts check this 2 page thread read it all....http://www.xoutpost.com/bmw-sav-foru...-8-owners.html
2. I think that was on high all leds lit.
3. to be honest I hated math so tons of googling found people that used that thermistor on bmws.
Also i was trying to match or stay near bmw reccomended temperatures.
i dont have it on this pc but if you go to the wds site and look up rear seat heating it will show you the temps the elements are supposed to be at for stage 1 and stage 2. rear seats are dual stage. front seats are 3 stages.

hope that answers your question if not i will post the wds guide i used.

1 other thing cool remember thermistor is only needed if you have old heating elements that are 1.. only 1 stage meaning get hot or turn off.
2. only 2 wires.

Most newer elements are 3 wires and already have the themistor in them.

[aimtimes100]

ok this was only done for the rear seats, does anyone happen to know how the process would be if you wanted to add heated seats to the driver and passengers seat?

[nigwhyrito]

Originally Posted by aimtimes100

ok this was only done for the rear seats, does anyone happen to know how the process would be if you wanted to add heated seats to the driver and passengers seat?

Aimtimes are you still looking for an answer to this question if so I can give you tons of DIY articles for this. The front seats is documented even with video all over the net. The rear seats hardly any documentation.you have to buy the then switch console with the heated seat buttons.you have to jumper 2 wires, you have to add relays. you have to remove the leather and affix the sensor..let me know if you need a guide for the front seats google turned up so many searches when i was starting.

[cooluserid]

bmwman528e
OEM system is safer then retrofit:
It shuts down when thermistor is too hot or disconnected,
It regulates heating by using thermistor signal VS klixon in majority of retrofits;
Most of all it looks better. It is much easier to install then retrofit. Extra cost is $100-$150 (OEM switches and connectors). It is approximately 15 minutes to install OEM switches in the center console and relay in the trunk.

nigwhyrito: I repeated test that was described in post #25 and found that threshold is 4.5kOm for LOW (one LED on) and 3.5kOm for HIGH (two LED).

I selected 10kOm thermistor from DigiKey. It regulates heaters at 100F (LOW) and 110F HIGH. My heating pads (Carbon mesh from EBay) have build in klixons set for 140F.

nigwhyrito:I think your 100kOm thermistor will not regulate. Your heater is regulated by klixon (thermal protection switch). It is good to keep klixon for protection and not to use continuously. Klixons do fail and then heater will be running continuously without regulation.

[aimtimes100]

Originally Posted by nigwhyrito

Aimtimes are you still looking for an answer to this question if so I can give you tons of DIY articles for this. The front seats is documented even with video all over the net. The rear seats hardly any documentation.you have to buy the then switch console with the heated seat buttons.you have to jumper 2 wires, you have to add relays. you have to remove the leather and affix the sensor..let me know if you need a guide for the front seats google turned up so many searches when i was starting.

thank you for the feedback, but after seeing a few DIYs all requireing the removal of the seat and seat cover, i dont think ill be doing this one

[Helmuth]

Originally Posted by nigwhyrito

Aimtimes are you still looking for an answer to this question if so I can give you tons of DIY articles for this. The front seats is documented even with video all over the net. The rear seats hardly any documentation.you have to buy the then switch console with the heated seat buttons.you have to jumper 2 wires, you have to add relays. you have to remove the leather and affix the sensor..let me know if you need a guide for the front seats google turned up so many searches when i was starting.

Hi nigwhyrito,

would be VERY interested in a guide for dummies for heated rear seats. I already have the console with the 2 switches, I have the heated backseat with the original plugs coming out of the seat but I have no cabling below the seat and maybe no relay (no idea where that has to be).

Thank you

Helmuth

[bmwman528e]

It would 100x easier just to run the aftermarket heaters on their own wiring and circuits and then just use the Factory X5 Heated Seat button and get it to work with the new wiring.