Retro fit heated seats into non loom car

bigwinn

bigwinn

Elite
 Lincoln UK
Site Supporter
I've just done this to my Jan 05 build 2.2 and thought I'd write it up for reference

Big thanks to Rob
zulu4
Click to expand...
for all his help and guidance

The car had non heated M Sport seats which I've refurbished and fitted generic heating pads from eBay to. As they aren't selling I thought what the hell lets pop them back in the car and see if we can wire them up properly.

If fitting factory heat pad seats then there will be additional steps to cut the loom in but the principles will remain the same.

I used this guide here to point me in the right direction:

https://z4-forum.com/forum/viewtopic.php?t=128827

This retrofit guide really helped get my head around how simple it is to do

https://www.keepandshare.com/doc2/119303/z4-retrofit-heated-seats-pdf-339k?dn=y&dnad=y

And this wiring diagram was superb

Screenshot 2022-06-20 at 21.53.56.png

They pointed me to needing a few bits, which made the job easier but not essential as there are ways of cutting into looms/connectors etc.

From eBay for £6 "Wiring Set" 61116930656- which gave me the main power cable and plug that sits behind the main switches
From eBay a heated switch set £35
From the forum a set of loom plugs from a scrapper car- I didn't use these in the end but it helped me picture stuff
From eBay some 10k thermistors
Various connectors etc from the garage

First- I ran the power cable from the relevant plug in the fuse panel and checked the fuse (F16) was in place. From pin 1 on the pink plug X11004. That ran to the brown multiplug behind the switches in the console (A169)

Opening the plug up (the black cover slides off to allow new pins to be inserted) the power cable then popped into hole 7. I'd ascertained that the wires I had from the breaker car loom would fit OK and I lined up cables running to the seat area for:

Drivers seat power and thermistor power (2 cables) from the brown plug from pins 1 and 20 (coloured green/yellow and white/blue respectively)
Passenger seat power and thermistor power from the brown plug from pins 13 and 21 (coloured green/violet and white/green respectively)
A common earth each side running to the earth point at the fuse box which would service the negative of each seat pad and the negative side of the thermistor for each seat

I popped the thermistors into the seats near the pads and ran all the wiring under the carpets and through the centre console.

Once all connected I have to admit I expected a flashing green light on the switch or a quiet pop of a fuse, but no: it all worked swimmingly!

If anyone needs guidance in future drop me a line and I will do what I can to assist!

Cheers

Stuart

IMG_5327.jpeg
existing switch compared to the breaker loom

IMG_5428.jpegIMG_5429.jpegIMG_5452.jpegIMG_5453.jpeg
 
Good afternoon!

My name is Javier, and I'm writing from Spain with the help of Google Translate, so please excuse any spelling mistakes.

I'm contacting you, especially @bigwinn and @Zulu4, seeking help with installing a heated seat system in my 2006 Z4 3.0si.

Originally, my car had standard seats with electric adjustment and heating. I bought manual sport seats without heating. I swapped the chassis to keep the electric adjustment and purchased the heating retrofit kit available for the sport seats, taking advantage of the fact that I was going to reupholster them anyway:

www.hubauer-shop.de

BMW original Calefacción de asiento por capas (52107895856)

Seat heating-pad parts spare part for BMW Z4 from the assortment Front seat - buy fairly Seats at HUBAUER-shop.de ✓ Your certified and authorized dealer 4.7 ☆ Over 50,000 happy customers!
www.hubauer-shop.de www.hubauer-shop.de

I made the mistake of not researching it properly, and after installing everything and putting the sport seats in the car, the heating doesn't work.

This is a diagram of what I have installed. As you can see, connector 1 is missing the backrest heating element, and connector 2 is missing the seat cushion heating element with the temperature sensor.




To solve the installation problem, I'm considering the following options:

Option 1 - Close the circuit by connecting connectors 1 and 2 and install a thermal sensor. I'm unsure if the thermal sensor could be a 10k Ohm one like this: https://ebay.us/m/7OF3xX
Or install a thermal sensor that I would take from the original heating element of an E46 3 Series.
This way I wouldn't have to remove all the upholstery, but I would only have heating on the sides of the seat.

Option 2 - Install an original heating element from the sport seats of an E46 in the seat cushion and a universal heating element in the backrest.
It might be possible to connect the side heating elements, but keep in mind that these side heating elements have the plug that connects to the yellow connector on the seats.

Option 3 - Install universal heating elements on both the seat cushion and the seat backrest, connected to connectors 1 and 2. As with option 1, it would be necessary to install a thermal sensor, perhaps a 10k ohm sensor or the original one from an E46 heating element.

If I'm not mistaken, @bigwinn and @Zulu4 have managed to install universal heating elements that work with the car's original buttons and all three heat settings.

Please, I need explain me in detail how I could operate my seats, if possible, using each of the three options.

Keep in mind that I have no knowledge of electricity or electronics. I would share any information you provide with my mechanic.

Thank you in advance.
 
j.calvo said:
Good afternoon!

My name is Javier, and I'm writing from Spain with the help of Google Translate, so please excuse any spelling mistakes.

I'm contacting you, especially @bigwinn and @Zulu4, seeking help with installing a heated seat system in my 2006 Z4 3.0si.

Originally, my car had standard seats with electric adjustment and heating. I bought manual sport seats without heating. I swapped the chassis to keep the electric adjustment and purchased the heating retrofit kit available for the sport seats, taking advantage of the fact that I was going to reupholster them anyway:

www.hubauer-shop.de

BMW original Calefacción de asiento por capas (52107895856)

Seat heating-pad parts spare part for BMW Z4 from the assortment Front seat - buy fairly Seats at HUBAUER-shop.de ✓ Your certified and authorized dealer 4.7 ☆ Over 50,000 happy customers!
www.hubauer-shop.de www.hubauer-shop.de

I made the mistake of not researching it properly, and after installing everything and putting the sport seats in the car, the heating doesn't work.

This is a diagram of what I have installed. As you can see, connector 1 is missing the backrest heating element, and connector 2 is missing the seat cushion heating element with the temperature sensor.




To solve the installation problem, I'm considering the following options:

Option 1 - Close the circuit by connecting connectors 1 and 2 and install a thermal sensor. I'm unsure if the thermal sensor could be a 10k Ohm one like this: https://ebay.us/m/7OF3xX
Or install a thermal sensor that I would take from the original heating element of an E46 3 Series.
This way I wouldn't have to remove all the upholstery, but I would only have heating on the sides of the seat.

Option 2 - Install an original heating element from the sport seats of an E46 in the seat cushion and a universal heating element in the backrest.
It might be possible to connect the side heating elements, but keep in mind that these side heating elements have the plug that connects to the yellow connector on the seats.

Option 3 - Install universal heating elements on both the seat cushion and the seat backrest, connected to connectors 1 and 2. As with option 1, it would be necessary to install a thermal sensor, perhaps a 10k ohm sensor or the original one from an E46 heating element.

If I'm not mistaken, @bigwinn and @Zulu4 have managed to install universal heating elements that work with the car's original buttons and all three heat settings.

Please, I need explain me in detail how I could operate my seats, if possible, using each of the three options.

Keep in mind that I have no knowledge of electricity or electronics. I would share any information you provide with my mechanic.

Thank you in advance.
Click to expand...

Hi matey

If your car had heated memory seats previously you haven’t got to re-wire anything on the car.

I’m not familiar with the retrofit kit you have fitted to the seats. What I would check is the following:

That you have continuity from the +ve and -ve feed wires from the seat plug (which will be there from the car) from there into the seat and into the heating elements. The other one to check is that you have +ve and -ve feed into the thermistor in the seat pads to monitor overheat

What do the heating seat buttons do- light up and go out in 2-3 seconds?
 
The seat heating pads (of which there are 4- base, back and 2 wings) all lead back to one connector which then leads into the male part of the seat plug
 
bigwinn said:
Hi matey

If your car had heated memory seats previously you haven’t got to re-wire anything on the car.

I’m not familiar with the retrofit kit you have fitted to the seats. What I would check is the following:

That you have continuity from the +ve and -ve feed wires from the seat plug (which will be there from the car) from there into the seat and into the heating elements. The other one to check is that you have +ve and -ve feed into the thermistor in the seat pads to monitor overheat

What do the heating seat buttons do- light up and go out in 2-3 seconds?
Click to expand...


Hi bigwinn! Thank you so much for your quick reply.

Actually, I don't need to rewire anything; I just need to fix the resistor installation.

The resistor I installed is the original one from the bolster:





Imagen cortesía de @PawnSacrifice


The booster heating element is connected into the male part of the seat plug.

When I press the seat heating button, all three LEDs light up, but then immediately turn off.

The wiring is open because the heating elements for the seat back and seat cushion are not connected. I also don't have a temperature sensor.

I've read @Zulu4's guide:


I'm not sure, but I think that to be able to use the original seat heating buttons with universal heating elements, you use a 10K ohm NTC thermistor

I've also read your guide:


If I'm not mistaken, you made the seat heaters using universal components.

Were you able to get it working with the original seat heating buttons? With its 3 heat settings?

Did you use a 10K ohm NTC thermistor like this one?




I have the bolster heating element installed and it is connected to the male connector of the seat. Perhaps the simplest way to operate it could be to close the electrical circuit and install a heat sensor.

My mechanic thinks it might work by joining the connectors for the missing central heating elements (connectors 1 and 2 in the image), and installing a 10K ohm NTC thermistor.

 
Last edited:
I understand more now- ok

I agree with what you and your mechanic propose- I think you can manually wire the elements in and insert the thermistor

I used thermistors just like the ones you pictured and buried in the seat base

Hope that helps

Stuart
 
bigwinn said:
I understand more now- ok

I agree with what you and your mechanic propose- I think you can manually wire the elements in and insert the thermistor

I used thermistors just like the ones you pictured and buried in the seat base

Hope that helps

Stuart
Click to expand...

Good morning bigwinn.

If I'm not mistaken, you made the seat heaters using universal components.

Were you able to get it working with the original seat heating buttons? With its 3 heat settings?

Did you use a 10K ohm NTC thermistor?
 
j.calvo said:
Good morning bigwinn.

If I'm not mistaken, you made the seat heaters using universal components.

Were you able to get it working with the original seat heating buttons? With its 3 heat settings?

Did you use a 10K ohm NTC thermistor?
Click to expand...
I used aftermarket seat heating and a 10k thermistor

I was able to get it to work with the original buttons

Your best bet here is using the wiring diagrams to help you identify the right wires for the power supply and thermistor
 
As I said before, I have the bolster heating element installed and it is connected to the male connector of the seat.

if this is the heating element that is connected to the male connector of the seat, could it be that it has a temperature sensor?

The connectors for the heating elements have two wires, one green and one brown.

The connector that plugs into the seat's male connector has several more wires. Could one of them be for the temperature sensor?

However, looking at the following image, it seems more likely that the connector intended for the seat cushion heater is actually designed to receive the temperature sensor, which would be located within the seat cushion heater itself. In fact, it has a third gray wire.

 
bigwinn said:
I used aftermarket seat heating and a 10k thermistor

I was able to get it to work with the original buttons

Your best bet here is using the wiring diagrams to help you identify the right wires for the power supply and thermistor
Click to expand...

Thank you bigwinn!!

This is great news for me. It's confirmed that it's possible to make the car's original seat heating buttons work with universal parts, while still maintaining the 3-level heat option.
 
j.calvo said:
As I said before, I have the bolster heating element installed and it is connected to the male connector of the seat.

if this is the heating element that is connected to the male connector of the seat, could it be that it has a temperature sensor?

The connectors for the heating elements have two wires, one green and one brown.

The connector that plugs into the seat's male connector has several more wires. Could one of them be for the temperature sensor?

However, looking at the following image, it seems more likely that the connector intended for the seat cushion heater is actually designed to receive the temperature sensor, which would be located within the seat cushion heater itself. In fact, it has a third gray wire.

Click to expand...
I think that is correct and where the thermistor sits hence the additional grey wire
 
j.calvo said:
Good evening, bigwinn.

Could you confirm that this is the temperature sensor I need?

ebay.us

Thermistance Thermistor NTC MF52 ±5% B 3950, 1K à 100K ohm, de 1 à 100pcs | eBay

Las mejores ofertas para Thermistance Thermistor NTC MF52 ±5% B 3950, 1K à 100K ohm, de 1 à 100pcs están en eBay ✓ Compara precios y características de productos nuevos y usados ✓ Muchos artículos con envío gratis!
ebay.us
Click to expand...
I’m not qualified to say it is or isn’t

But as long as you connect a thermistor in the circuit it will allow the seats to operate
 
Good morning.

The day finally arrived when I could find the time to solve the problem with the seat heating.

In the end, it turned out to be very simple.

The first thing was to check if the circuit was open, since the heating elements for the seat back and seat cushion weren't installed. The circuit was closed! Therefore, it wasn't necessary to connect connectors 1 and 2 in the following image:




The next step was to install the temperature sensor.

For this, I used connector 2 in the previous image, as it includes the gray wire intended for the temperature sensor that the seat cushion heater would have had.






I connected the temperature sensor to the gray wire and the brown wire (ground), and I managed to insert it between the seat upholstery and the cushion heater. To do this, I only had to remove a small section of the upholstery on the side.

Once the job was finished, I just had to put the seats back in the car and enjoy.

Thank you so much, @bigwinn; without your help, it wouldn't have been possible.

Cheers!
 
j.calvo said:
Good morning.

The day finally arrived when I could find the time to solve the problem with the seat heating.

In the end, it turned out to be very simple.

The first thing was to check if the circuit was open, since the heating elements for the seat back and seat cushion weren't installed. The circuit was closed! Therefore, it wasn't necessary to connect connectors 1 and 2 in the following image:




The next step was to install the temperature sensor.

For this, I used connector 2 in the previous image, as it includes the gray wire intended for the temperature sensor that the seat cushion heater would have had.






I connected the temperature sensor to the gray wire and the brown wire (ground), and I managed to insert it between the seat upholstery and the cushion heater. To do this, I only had to remove a small section of the upholstery on the side.

Once the job was finished, I just had to put the seats back in the car and enjoy.

Thank you so much, @bigwinn; without your help, it wouldn't have been possible.

Cheers!
Click to expand...
Glad you got it sorted. Well done
 
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