Heated seat retrofit with pictures
 

Been searching on this forum for pics of rear heated seat wires and could never find one. Asked a couple people where the wires are hidden or at least the location.. No answer.. Well today was nice day so here are my pics of my X all ripped up for anyone that wants to know for future .. Also to come will be pics of the rear footwell lights added.. Aparently they are prewired too. So in a nutshell the connectors are zip-tied under the front drivers seat.. but at the front of the rear carpet.. close to the back part of the front door pillar.

This is some great investigation. I've been meaning to do this for a long time and possibly retrofit some aftermarket heaters using the oem switches. Good job on the tear down and pics!

Did you end up pulling the drivers seat out completely or just slide it backward? And the console...did you need to disassemble it?

Nice work, but does your rear seat bench have the heating elements embedded within it?

I unbolted drivers seat and slid it backwards.. battery is disconnected to.. was worried about airbag light buti never even disconnected that connector.
no my bench does not have the elements... I have some aftermarket from my last car Im going to retrofit. just need some hog ring pliers or maybe small zipties. I have all the wiring diagrams from wds site .. studied it long time. tommorow will be a day of testing wires and possibly putting in thr rear footwell lights. 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.

Sir, Mr. Nigwhyrito

you are my hero, I am searching such a post since one week now. But my problem starts when I look for the plug below the rear set - it was also dirty there :-) - but no plug ............

Did you have to add a relay in the trunk?

Best regards,

Helmuth

Hey nigwhyrito...sounds like you're doing an aftermarket solution that I've been thinking about for the last 3 years. Let me know how it turns out or if you can document the heating elements used and wiring that you're putting in place. I'm not much of a wiring guy, but I've read all the wiring diagrams and understand what goes where and does what, but actually wiring it together with aftermarket elements is a bit of a mystery for me.

Also, if you don't have the relay in the rear fuse panel, you might need to buy one.

Yes you defininetly need the the relay.. Its a light green one has 5 pins. Called k93 unloader relay terminal 15. Today I finshed installing the rear footwell. Now I have to trace the seat heater elements out with and ohm metter to match what the bmw is looking for.. stay tuned for more as it comes ( dangit...My stupid butt learned the difference today between disconnecting the battery and disconnecting the ground terminal comming off the battery. Started x5 after taking seats apart again x5 wouldnt start I almost did a #2 in my pants.. Then she started beeping.. like the doors were locking and I could here the relays in the back clicking away..I checked the votlage out of battery was at 8v.. jumped and everything good except... now I got the dreaded Airbag light and ses light... doh...moral of story disconnect battery at post... disconnecting the ground near the power distribution will screw you up sooner or later.

Here is the wiring diagram for one side. Maybe you already have that. +12V to white/yellow ground to brown, thermoelement is connected to yellow/brown.

Thanks helmuth and yes I do have that diagram.. Im just waiting on a nice sunny day hopefully the weekend.

Did you have your plug below the rear set "simply lying there" or did you have to find it. On mine I was not able to find that plug :dunno: I pulled on all cables there ........

What year is your X5? This was interesting to me but I don't know if my X5 is pre-wired as rear heated seats wasn't offered until 2002 (mine is a 2001). If yours is 2000-2001 that might explain why there are no wires.

Mine would be a 2002 3.0d European version.

I don't know if I've ever seen anyone take apart the seatbacks to get the leather off for back heating elements, but it'll be an interesting project. Nigwhyrito, are you going to clip off the OEM connectors and solder in new multipin connectors?

Answer to helmuth.
I have an 06 3.0i USA. my plugs were under the seat.. which made me want to start the project since it was already wired.

Answer to nra0707 -
yes im going to pull the hog rings off. add some aftermarket elements then put the leather back on and put some more hog rings.. or zipties depending how I feel back on. I am going to be soldering to the bmws wire harness just tapping into the wries that way if ever in future i find a rear heated seat or i sell my x.. I will still have the factory connector in good shape. Im just getting upset though because i think the bmw uses a dual stage heat elements for the rear seats. the one i have is a single stage elements from my kia sorento before i crashed it. Im may have to get a new temp sensor from digikey to make it work.. but there about $8 bucks so no worries there. if i cant make them work then i have to purchase the dual stage elements $160 buck ones off the internet.

Sorry everyone got side tracked.. things that through me off 1.. bmw schematic is actually backwards.. the one you pointed to helmuth is actually backward on wds bmw reversed the wire code up on that page. you have to look up this schematic x337 that actually is the rigth schematic for the wiring. 2. monday driving home caught a flat tire. had to put everything back together so bmw would replace it under warranty. 3 my seat heat elements are 2 wires they are wired in series where as bmw uses there in parrallel and use 3 wire. Still trying to source the thermistor on digikey and mouser website so I can add it to the circuit. My elements do have temp switch tested it out today with a heat gun and it went from 2.3 ohms to 0/infininty.
4. its freaking cold..lol. in my searching I found some good info.
seat heat temperatures
NTC thermistors
3 stage switch for front seats but im doing the rear and they are set by bmw for
2 stage switch.
stage 1 high = 44ºc
stage 2 med = 39ºc
stage 3 low = 35ºc
input = 120w
95ºc turns off
so this is what i think i need from mouser or digikey 2 NTC thermistors 1 for each side. I guess
at 10kΩ and operating temp of 40º C and 120w with 10 amp current not sure if
they will work any electronics engineers? Im working the circuit over with my dad in his spare time.. I do not feel like buying new aftermarket elements.
also found some good info here about range rovers which were i think made by bmw.
Heated Seat Temperature Upgrade on Range Rover 4.0/4.6
i did finish the retrofit of the rear footwell lights that was done in under 30 mins.

Great, just did mine yesterday

NIK wheres the pics?

Problem statement: I have the original heatet rear seat and the original switches but my cable to the seat is missing so it seams I am somehow lost. Was always hoping that all cabling would be there in a 2002 3.0d.

I believe the + cable should come from the relay in the trunk - this might not be a problem but how do I connect the switches and the temerature measurement sensor?

Has anybody solved that in the past?

Are the rear footwell light lenses the same as the front footwell light lenses? I can't find a part number on RealOEM. I would assume it's part 9? http://www.realoem.com/bmw/diagrams/a/p/220.png

mm, I did take one or two pics, I will post if you guys want it. I baseicly Removed Center console, Drivers side seat and pulled the carpet. there are two plugs that I took and put heated seat switches on. then Replaced the backseat.

XNSF they are not the same the rear footwel lights look like the pic attached they are larger than the normal door lights.
they have 2 nuts each that secure them to the floor. the bulb is 8.00 at the stealer. Its the same bulb in the doors I dont have the part number off the top of my head I called the dealer he quoted me 36 bucks for the 2 lights and then 16 bucks for the bulbs messed that up inpic.. I ended up getting the lights from a parted out thread. Just take a razor blad to the carpet inside the pre cut mold. I made an x on to make the fit as tight as possible then I added some foam from a hardrive case to make the carpet look nice and flush with the lights. the result is below. Now 2 things I need the exact paint on the speaker grilles so i can paint my sub, and my dad or some engineer to get back with me on the parts to order from mouser.

helmuth do you have a pic of what your missing. You said you have the rear heated seats so the wires are dangling at the bottom of the seat. But you are missing the wire harness that goes from the relay K92, the ground in the back x492, I think that is the x337 wire harness you are missing that also goes to x792. you may want to contact Alpine m3 in his 4.6 part out thread see and see if he wants to get rid of his harness since i bought hos switches. Be warned that seat heater harness x337 and x792 go all the way to the front fusebox theres a fuse up there for rear seats and they connect in the back to the main fuse panel to. I was lucky my 06 was pre wired.

If I'm not mistaken, even if the wiring harness is present for Helmuth or he can source it, doesn't he need the back rest heating elements to complete the circuit? I would suspect that just plugging in the bottom elements wouldn't be enough for the heating elements to work.

To nigwhyrito: Exactly what you wrote. I have the rear heated seats so the wires are dangling at the bottom of the seat. The reason for that is that I got a leather rear seat cover with these elemets and had a guy mounting them. What I have additional (since yesterday) are the rear seat heating switches in original. And you are right again, I am missing the harness from the relay K93 to the seats (part of that might be the wiring from the temp sensor to wherever). Really a great idea to source that harness from Alpine M3 but I believe first I need to disassemble my X in order to be sure that the cabling to the switches is there. BUT - when this cabling is there... why is then the cabling to the heated elements missing.

I believe you get my point.

To nra0707: the backrest heating elements are connected in parallel to the seat elemets. So from a technical standpoint no need to have them.

To Alpine M3: not sure if you want to disassemble your X in order to tell me a price for the cabling............ ???

Thanks everybody.

:thumbup: its working the 2wire conversion to 3 wire the elements got hot and the oem switches leds came on and each level worked. So im 75% complete

-whats left-
record exact resistance ratings
order thermistor to take the place of the variable resistor
put thermistor into the seat heat element not the backrest element.
rewire it all into molex connectors
then take the leather covers off
put the covers back on.
make the wife drive more so I can enjoy it lol.
take the X in to have the airbag light reset keeps comming on for
the pass... side
--my schematic attached for left side.---

Awesome work!

Ok, so I have alrady Put the Buttons in the place, Now I have got the rear Heated seat, going to replace it in few days. Nothing else is needed for them to light up right? Thanks

Nigwhyrito: I was just re-reading your previous post about buying 2 NTC thermistors. I thought NTC decreases resistance as temps increase. Isn't this opposite of what you want? PTC thermistors will increase resistance as the temperature increases, which effectively reduces/cuts current as the surface temperatures of the elements gets too hot.

Well NRA you and my dad both said the same thing.. but the truth of the matter is on the wds website the signal says NTC. so im just going by all the research I have read reagarding bmw and the range rover is the elements have NTC thermistors..so i guess we'll see when i finally order one. Also my heated seat elements have a thermostat the little metal circular thing. I tested it with a heat gun when it go to hot the circuit was broken.

Oh, you're right...it does say NTC in the WDS. I didn't even notice that. I'm not going to question the BMW engineers though it does seem counterintuitive. There must be a reason for doing it that way unless they were just lazy and generically labeled them NTC thermistors. The Range Rover link's description of the cantherm thermal switch sounds a lot like a PTC thermistor. Sounds like your elements' circular/disc thermal switches will be added insurance against overheating.

Updated pics 80% done
 

Well this project still isnt 100% done. Just got some time to order the thermistors.. Wired them up. Tested and it worked. So I removed the pot (variable resistor) and soldered in the thermistor. TEST was succesful.
NOW still trying to source OEM connectors got my parts guy hunting and he is :confused:.. Please can anyone with rear heated seats look at the connector under the rear seats and give me the numbers for the female ends. the 6pin connector and 2pins. Ordered my hog ring pliers so I plan on taking the leather covers off this weekend.
heres some more pics.. this would be an easy mod for those with three wire heat elements .. But mine only had two wires.. But now I have three.;)

Figured I post the rest of the pics..

and still more.

So mad.. found this foam lying around but not enough of it. I could have added it to the seats to make the contour different and possibly more comfortable. Need at least 4 sheets per seat. Oh well will do this again when I have my computer fans circuits and perforated leather ready to go. Will I do this for you you ask? Only if your trading me your working oem navi becuase you just bought that kickass pioneer or dynavin and want to sell your oem nav..:rofl:

My wrists are sore though from all that hog ring cutting.

Bro, I hope you know what you're doing, even so I would still keep a fire extinguisher in the car just in case.

I studied that circuit thoroughly plus theres a 20 amp fuse on it. I verifed and used the the same guage wire as bmw, and sourced there exact oem connectors. I mean Its pretty much oem except the elements and the thermistor.

Nice work. Was wondering if you'd wrapped up the project. I'm going to tackle this in the fall before the winter chill.

I guess im have to start a new thread for cooling seat mod.
I figure I have 3 alternatives. 1. use pc fans. - I read the new beamers have 9 fans for cooling. I was thinking maybe 4 per rear seat and 6 per front seat. 2 in the bolsters.
Idea #2 run the vent from the ac under the seat into the front seats. Possibly use some flexible material and black duct tape. flexible so i can still move my seats around. Again going to have to talk to a leather shop about some perforated leather.

idea #3 somehow run the vents from the center console into the rear seats, Probably come up under my dvd player.. Be honest I dont use it.. So im going to replace it with a wdtv or soemthing.

Idea #4 find out if the first aid boxes are big enough for a ps3 slim then source a good inverter that will be wired to the battery.

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

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.

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

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.

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?

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.

hmmm bmwman528e - Curious were you talking to me. Reason I ask is because thats what I did. My aftermarkets were single stage heaters. The bmw switch and electronics are for a dual stage heater. So without the thermistor the BMW switch would not work. My aftermarket kit was for kia sorento that I crashed a long time ago. So when you say 100x easier you must have meant for me to buy another aftermarket kit. That 1 already was dual stage heaters. 2 Made for bmw 3. spend money that I didnt have to spend ? Just confused by the last post thats all.:confused:

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.

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.

Thanks cool for the concern but I actually removed the klixons or as my dad called temp switches. I didnt like the fact the seats were not as hot. It kept kicking in to fast. My thermistor in the seat lements are working fine. I tested with a temp probe 3 distinct different temps 0ff high and low.. crap I forgot what they were but they were the same as what bmw posted. Also you said 100kΩ, i thought I purchased 2: 50kΩ.
50kΩ per circuit. I thought the seat heaters left and right were considered 2 different circuits. So are you combining total resistance when both are on at same time?

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

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

For those interested, I got the part number for the footwell lights:

2 pcs footwell lights - 63316962035
4 pcs plastic nut - 16131176747

To answer your question No they are a bit larger plastic lenses then the other footwell lights . I think the bulb was different to Ill have to check.

I got mine from a parted out x deal.

top post mate,
i got the wires under my back seat so i followed your instructions and bought the switches and then found the wires under the front seat (passenger if in uk)
i have installed everything but have no power in switches, i have read the posts and a k9 relay keeps popping up.
Where is the realy located and do you have the part number for said relay if there is not one in my car.
Tar

"Yes you defininetly need the the relay.. Its a light green one has 5 pins. Called k93 unloader relay terminal 15"

Is that what you are referring to?

If so this pic might help you.

Is this how the fuses area in the back of your X5 look.
Mine has these relays. I bought the rear seat heat relay off a guy parting out his X.
just to confirm you stated you have the wires under the rear seat. Okay you have half the wires right. Meaning to completeley remove you rear seat do you have disconnect any connectors. If no coonectors then that mean your rear seat doesnt have any heating elements. So thats another reason why the switches wouldnt work. Which means now you have to go out and do 1 of these.

1. buy heated seat elements Preferably a 3 wire design
2 buy a rear seat from a parted out x with the elements already installed. mainly 4.6 and 4.8 have them. Not my poor 3.0

3. Buy just the rear leather cover from a parted out X as i think the elements are sewed in.

again i started this mod because i had some leftover seat elements from my last vehicle that i never installed.

Let me know if you need the actual part number of that relay. Im sure real oem has it.

OMG i am so glad i took this pic today. My fuses 80 and 81 have the wrong amps. There supposed to be 20 not 25. My x5 is going turn into a phoneix and burn up. Going to autozone now.

cheers mate, i got the part number earlier and bought it £10.
every thing works perfect.
Thanks

FAIRLY easy to retrofit PDC, I did it on my 2002 X5.

Pulled this upgrade off. Heated rear bottom seat only, not the rear uppers. Picked up a rear seat bottom, switches and relay at a wreckers. Wires were under the driver seat for the switches (just needed to be fed up through the console), power wires under the rear seat. I have to switch seat leather, but I tested each side and they are good. Tossed in the relay and life is good. Kids will be happy in the cold months :). This write up helped locate those switch wires quite nicely. Thanks!

There is always a snag. The heater elements are stitched in to the rear leather. It will be a more involved process, but I've started dissecting the donor heated seat and will figure out a way to transfer the element over to my seat. It just won't be easy. I seem to attract these projects.....

I have question about strange option in my car! I have my e53 for three years! My car has Italian package and has no heated seats! But I have felt sometimes in cold weather like my ass had been warmed! I did not pay attention to that... I thought it is because of material in seat! My wife just said she has very warm ass during driving! Could it be automatic option for winter?

It's a good question, however E53 don't have automatic seat heating. It's activated by the switch strip just in front of your front ashtray. Switches are at the extreme left and extreme right.

Italian market E53, I have one originally with cloth mechanical seats. I retrofit heated leather sport seats up front, leather rear (no heat) and the matching door cards. Fairly easy to do, I did a write-up on this ~4 years ago.

Someone might have retrofit a basic panel in the seat, have you checked?

Is it heated?

Just changed central console from 2005.! Full buttons...everything works... except heats, of course!

What about relay? Does it have it under glove box like heated wheel relay?

I did my heated rear seat retrofit a while back, easy!
the relay is the first one (light green) in the REAR fuse/relay compartment when you open the rear panel (where the subwoofer and gas cap release are)
I was lucky when I did mine, because I got seats that were the same color and material as mine.

I also did the PDC retrofit, the only un-nerving part was cutting holes in my bumper!
but they were marked out very well, and it was pretty simple to do!
running the wires was easy as well.

Found the plugs under my seat the other week when I was doing my fuel pump. Sourced 3 other x5s with black heated rear seats so off I go to nab some stuff. Hope one of them has a good set of PDCs and folding mirrors as well.

I don't know why but all of a sudden I am looking for used rear heated seats to swap -

I bought relay for rear seats...but that relay in trunk is only for rear seats! I will take off glove box and take a look...there is place for 4 fuses approximatrly!

I am not sure about front heated seats to swap them! Because I have 18 wires like that full console I changed it! My seats look the same underneath like those who has heating! Plus I have now tyre pressure control...of course it doesn't work... :D I do not have sensors in tyres!

Can't seem to find your thread on this. Is it as simple as getting a set of heated seats and the correct switching center? Or is there actual wiring that needs to be done?

I carried out this retrofit nearly six years ago and posted information for this (look under my id). In short, for the front seats you need to

(a) swap seats and plug in existing connectors to the car
(b) install the small control panel with switches (just above the front ashtray) to one with the switches for front seat heating.
(c) The passenger seat will work with further changes. The driver's seat will require either a jumper wire (an Austrian fellow posted this, based on his experiences), which I did to get the driver seat working.

The correct way is a add the relay that factory power seat cars have. It is located in the relay cluster of the FRONT fuse box. Part number is 61.35.8.365.960 (black, 5 pin).

You MIGHT need to add the fuse (front fuse box) for the seats, check your car. I didn't need to do so, even with a car with mechanical cloth seats.

I got rear heated seats and my car was pre-wired so I was able to connect them.
Then I got the wires for the switches from under driver's side carpet.
I see that Relay 1 in the trunk is responsible for rear heated seats.
I tried swapping relay 2 and relay 3 into the relay 1 slot.
When I push on the switch, it only illuminates for a second and that's it.
Anybody had that happen?

Check the seat heater lines for a short?

You're probably right since my front driver's seat burned lol
https://i.ibb.co/qJsqQQt/20210502-192922.jpg

I guess the rear seats are on a separate circuit.
So I measured resistance on two connectors that go to the rear back rest. On one the resistance is 24.84 and on the other one 044.1
I'm no electrician but 044.1 seems like too little resistance? Those wires should be negative and positive, so the resistance should be infinite, since negative and positive shouldn't be touching each other, at least as far as I can tell! Not sure if 24.84 is acceptable though.

All fixed now. The problem was that I didn't connect the seat bench, just connected the back rests and I guess it needed the bench plug to be connected to close the circuit.

Hello, I have the same e53 2004 facelift version, I'm interested in what I need to install rear seat heating? Is it possible to put heaters in the seats myself without buying new seats (and if you can leave me a link from those heaters that should work well on a 2-stage heating switch)?

You can find seats at a salvage yard. Is your car pre wired? You need the switches to turn on the rear heated seats. Check under your carpet by driver's seat, there should be a connector. Can you find it?

Yes I have a connector, is it possible to put heaters in these seats now and it works properly


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Yep just connect a heated seat to the connector under the rear seats and connect the two switches to the connectors. You'll be good to go

You didn’t understand me, I would buy aftermarket seat heaters and install them in my seats if possible. I don't know if all the heaters can work on this installation in the car (more precisely it confuses me that the switches in the car have 2 heating stages so I don't know how it affects the heaters, does it just increase the voltage when it is compressed 2 times or)?


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I would think that it increases voltage for more heat.
I'm sorry I can't help with aftermarket heaters for the seats, never tried those.
I'd suggest getting used rear seats, then it's plug and play. That's what I did. They're super cheap at salvage yards.

Yeah. Do that. :iagree:

Most rear seats are in great condition and you'll save yourself the trouble of trying to match amperage to the car so you don't start the car on fire!

i will try to find a car scrap, that would be best


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