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How to Enable Heated/Cooled Seats - All Models

NC GTier

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Disclaimer: The below assumes some knowledge of wiring/assembly/safety/etc. It is written to the best of my knowledge and what worked for me. I am not responsible for any damage caused by following the steps below or any consequences. That's said, I have done the below on my cars and it worked.

Rule of thump: for any module to function, it needs four main wires: 1) hot, 2) ground, 3) Can bus +, and 4) Can bus -.
So the below is based on reviewing the electrical diagrams and lists the steps in order to route all these four wires to the H/C module.

If you think the below is too much trouble, I also build the custom harness and sell it for $300. It comes with my installation support.

20240208_183611.jpg


Worth mentioning, there has been a change in the wiring between 2017 and 2018. The H/C module was relocated from under the passenger seat in 2015-2017, to be combined (one black box) with the memory module under the driver seat (DSM - Driver Seat Module) in 2018+. That's said, the below will only explain how the H/C function will be enabled, and nothing about the memory function.

Please note, this modification assumes, you already swapped your base 4" small screen to the premium 8" screen with stock parts (screen and bezel), and that the bezel has the buttons for the H/C. Otherwise the H/C will not work. Also obviously you swapped your base cloth seats to premium leather seats (also stock).

What do you need?
1- two pigtails WPT-1279 available on ebay and Amazon, nothing expensive.
2- wires (a spool). I used wires gauge 14 for everything to be safe (only 4 wires needed to be 14 and the rest were less thickness), but I went with the thicker wires because that's what I had.
3- electrical connecting butts or any method to connect two wires securely. I also solder, to ensure strong connectivity and durability.
4- shrink wrap tubes and conduit wherever needed.

Premium leather seats come with two connectors in each. One (bigger size) plugs into the existing floor connector, and one (smaller size) that is extra and doesn't have a floor connector to plug into (in the base models). That's where the two pigtails will plug into (after building the harness). In fact, the harness you will build, will go straight from one seat to the other.

Each pigtail comes with about 1 foot of wire attached to each pin (16 pins total). What you need to do is extend this 1 foot wire by 6 ft and connect to the other pigtail. Pin 1 to Pin 1, Pin 2 to Pin 2 and so forth. The pin numbers are written very tiny near the edge pins. Be careful not to cross wires to the wrong pins.

Pins that are NOT used (you can remove them from the connector or just cut the wires in the back of the connector):
For years 2015/2016/2017: pin 11 and pin 14.
For years 2018+: pins 6, 11, 12, 13, 14.

After you're done, put your shrink wrap and conduit etc. Your easy part is complete.

Now that you have built your harness, you can go ahead and feed it from one side to the other under the carpet and under the center consol. You will need to pop the center console cover to pull the harness from one side to the other. To pull the cover, there are two 8mm screws on each side in the front hidden by a plastic cover, which you can pull by hands.
After you route the harness, be careful not to let your harness interfere with the emergency brake handle. Keep it away from the handle with zip ties or tucked away from it.

We will now move to second step. Feeding the hot/ground/MS CAN+ and MS CAN-

For 2015-2017 models with power seats (driver and passenger):
The H/C module is under the passenger seat (gray box). It takes its hot/ground from the existing floor connector. That connector for base models already has a ground shared between the power seat and the HC module (Pin # 8 Black/white wire). So nothing to do for ground.
For hot, it is not there, and you need to add it. There are many ways to do this, but I will only mention the easy lazy way. I just use the existing hot that feeds the power seat and combine it to use for H/C. In my opinion it is capable and doesn't blow the seat fuse even with both heats on and both seats moving. Pics below shows you two ways to do it. I prefer the bridging way. This is done in the seat connector, not the floor connector. That takes care of the hot.

Connecting the HOT.jpg
730250461.jpg


For 2015-2017 models WITHOUT power passenger seat or recaros:
You will need to pull a hot and ground from the passenger side kick panel. There is a connector that has these two wires with nothing on the other side, they are in fact routed there to use for H/C if the car was equipped with that. Be creative how to pull these two wires and route them to the seat.

For 2018+ with power driver seat:
You will need to do the same as above but for both, hot and ground, because the ground in the driver floor connector is not shared/routed to the H/C module. You can follow the bridge method on the driver seat connector. See pic above for hot, and pic below for ground. Again, this is the seat connector, not the floor connector. The pic shows both black wires bridged, and both green and violet wires bridged in the driver seat connector. Nothing to do with passenger side. Please use solder if possible to ensure strong connection.

730341236.jpg



For 2018+ with recaros or WITHOUT driver power sear:
You will need to access a connector by the driver side kick panel that has both ground and hot available to use (nothing on the other side of the connector), feel free how you want to tap these two wires and get them to the seat connector.

All models:
Now that hot/ground is there, will work on MS CAN + and MS CAN - (data lines):

There are different places in the car to pull the data lines from, but I choose behind the OBD (gateway module) connector. Relatively easy to access and close to the driver seat. The OBD module has a connector plugged into the back of it, you will need to unplug it and look for two wires: VDB06 (pin 23 Gray) CAN + and VDB07 (pin 22 Violet) is CAN-.

Resized_Screenshot_20240222_174804_Messages_1708642088597.jpeg


You need to tap into each one and feed these wires to the driver seat connector. I have to warn you, these wires are super thin and easy to cut. If that happens, just put a connecting butt and add your wires. Soldering recommended.

At the driver seat:
For 2015-2017:
The above two wires will tap into the harness you built. Pins 12 and pin 13.
the Gray goes to pin 12 and violet goes to pin 13

For 2018+:
The above two wires will need to route to your seat (big) harness. Gray to Gray/Orange, and Violet to Violet/Orange.

Screenshot_20240220_211148_Messages.jpg



Once you're done, you will be able to test everything. Your engine must be running when you test.

No forcan or programming needed unless you want to add the buttons on your screen.

ENJOY!

20190926_170840.jpg
s-l500.jpg
Non-Memory Drivers Side Wiring Diagram.JPG
Premium Seat - Control Switch.JPG
Wiring-Diagram-Passenger-Seat-Climate.JPG
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Cobra Jet

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Excellent tech write up and will definitely benefit others looking to do this swap!
 

Skywalker69

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Just finished my heated/cooled upgrade this week. 2016 Mustang GT 5.0 manual base. Base seats are both 6-way power seats.
I already swapped display 4.2" to 8" Sync 3. You will need that before upgrading, so you would have the buttons to turn h/c on/off.
The below assumes some knowledge of wiring/assembly/safety/etc. Ask as many questions as you want.
I didn't want the memory feature (to keep things simple), so everything below only focuses on enabling H/C.
Here is what enabling h/c involved:

1- Premium seats with H/C feature. I bought mine from ebay. They were dark brown/black.
The driver side airbag was blown, so I replaced blown airbag with the original base seat airbag (identical), and took the cover to a local upholstery place which did an awesome job stitching it back ($20 as I already had the cover pulled out, then I installed the cover myself). Anyway, that's one way to find less expensive seats. Mine cost $850 delivered (+ $20 to stitch it back). Getting covers out/in is not as complicated as you would think.

2- Two pigtails WPT-1279 (from ebay ~$50-60 each).

Premium seats come with two connectors each:
  • One (bigger size) - the same as base seat connector - will call it THE BASE CONNECTOR.
  • Second (smaller size) connector in each seat - will call it THE SECOND CONNECTOR. The two second connectors connect to EACH OTHERS. Yes, ONE SINGLE harness goes from the driver side second connector to the passenger side second connector. The pin-out is straight forward. Pin 1 to pin 1 and so forth for all 16 pins. Pins 11, 12, 13, 14 are not used (again, assuming you're giving up the seat memory feature).
I used 18 gauge wires for this harness (bought a spool from Amazon). The harness length can be 8-10 ft depends on where you want to route it under carpet. Just don't route it where you would rest your feet or anywhere it can be stepped on. Target corners and folds. You get the idea.​

Once you make this harness, all the remaining wiring will involve the base connector in each seat.

Few facts:
  • the h/c module is located under the passenger seat, and gets its wiring (hot/ground/MS CAN+/MS CAN-) from the passenger seat base connector.
  • The base-model base connector will not have HOT/MS CAN+/MS CAN- fed to h/c module, so that's what we will be adding. Ground is already shared/wired.
  • Pin 1 in the base connector is HOT and goes to the power switch (already there). Pin 9 is the other HOT that is missing, that goes to the h/c module. I personally used the same power switch HOT (pin 1) to feed to pin 9 (spliced it). Yes, it is meant to feed the power switch only (30 Amps), but I think this is not a constant power load, and should be fine to share it with the h/c module, which needs 30 Amps too. That takes care of HOT.
  • For MS CAN +/MS CAN-, I fed these from the bezel connector (FCIM). Pin 17 in the FCIM connector is VDB06 (Gray) CAN + and pin 18 is VDB07 (Violet) is CAN-. Splice these two wires and feed to the H/C module directly. They would go to pins 1 and 2 consequently in connector C3265C (the medium size connector connected to the h/c module).
Once you feed the hot/CAN+/CAN-, you will be able to test your build by turning h/c on/off. You will hear the relay in the h/c module clicks. That means your wiring is correct and you are done enabling h/c.

Treatable side effects:
  1. possibly the airbag light may illuminates after you connect the passenger seat. That's due to the occupancy classification sensor module (OCSM) may not be compatible between the base and premium seat. What I did, is switching the sensor between my base seat and the premium seat, and the light goes away. Don't cut the sensor tube, but replace the whole assembly - remove the seat cover and replace the whole sensor assembly (sensor+tube+pad). It is not as complicated to remove the cover as you might think.
  2. the premium driver seat may not move at all as the base connector in premium cars has memory feature, so hot will not feed directly to the switch power, but rather to the driver seat module which then feeds the power switch. I fixed that by cancelling memory in the seat. To cancel memory, I used both premium seat harness and the base harness (taken out). I had to break down both harnesses and build one harness that combines the h/c wiring from the premium seat and the power wiring from the base harness. there were only two wires that I had to move over from one connector to the other. No splicing/cutting involved in building this harness. This is basically the trickiest thing to do in this project. Not sure how to explain it further, but once you take both harness outside, you will start to understand the difference. Ask questions if you don't get it.
I included all wiring diagrams for everything. Ask if you have any questions.
20190926_170840.jpg
s-l500.jpg
Non-Memory Drivers Side Wiring Diagram.JPG
Premium Seat - Control Switch.JPG
Wiring-Diagram-Passenger-Seat-Climate.JPG

if you have another diagrams i could use them. trying to do the same thing.
 

Skywalker69

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Also did you have to buy a plug for the back of the radio for the heated and cooled switches to operate?
Thanks
 

ctandc72

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Also did you have to buy a plug for the back of the radio for the heated and cooled switches to operate?
Thanks
Doubt it - it's already in that part of the wiring harness - it's just enabled or disabled via Forscan programming I would think.
 

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Skywalker69

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Doubt it - it's already in that part of the wiring harness - it's just enabled or disabled via Forscan programming I would think.
Thanks I replaced my 4 inch with an 8 inch upgraded radio and there’s a spot behind that look like a plug was supposed to go into it.
 

Skywalker69

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Do you have any pictures of your wiring harness when you made it
 
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NC GTier

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Thanks I replaced my 4 inch with an 8 inch upgraded radio and there’s a spot behind that look like a plug was supposed to go into it.
If you already upgraded to 8", do you have the bezel with h/c buttons or the recaro (non h/c) bezel? Either way, you can use the screen buttons. Like ctandc72 said, you can add the seat buttons to your screen by forscan. Thats what I did. The only thing you need from behind the bezel is the MS can+/- wires which you will splice from the bezel connector, and feed to the h/c module under the passenger seat, like i explained above.
If you have the recaro bezel and want to buy the h/c buttons, I have one for sale $70, i will put on ebay.
Unfortunately i didnt take a pic for the harness, but like i said, it was 7-8 ft straight from the second connector driver seat to the second connector passenger seat.
I will post more related wiring diagrams soon.
 
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NC GTier

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Do you have any pictures of your wiring harness when you made it
More diagrams attached. Please note there are PDFs attached to the original post for more detailed wiring diagrams.
I printed all of them and spent night looking at them and building the whole thing in my mind, until the light bulb went off and started testing and everything worked :-)
The C315 connector in this diagram is the second connector in the passenger seat. The C3808 connector is the second connector on the driver seat. You can see the wiring between them, straight forward (pin 1 to pin 1 and so forth). One single harness. It doesn't go anywhere else.
The last pic is for the passenger seat wiring to the h/c module, which is already there, you don't have to do it. Since the h/c module is already under the passenger seat and already wired.
Driver HC Seat.jpg
HC Module.jpg
Passenger HC Seat.jpg
 
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Skywalker69

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Here is what I have the bezel with h/c buttons. I just need to know what wire plug I need to tap into on the bezel. Also switching out the airbag sensor from my stock seats to the new seats work to turn off my airbag lights.
Thanks
4988D8E4-F9DE-4E55-A2F8-49C1F93854A4.jpeg
59C5350D-4B18-4ABC-ACA2-663C5DA74C89.jpeg
 

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NC GTier

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Here is what I have the bezel with h/c buttons. I just need to know what wire plug I need to tap into on the bezel. Also switching out the airbag sensor from my stock seats to the new seats work to turn off my airbag lights.
Thanks
4988D8E4-F9DE-4E55-A2F8-49C1F93854A4.jpeg
59C5350D-4B18-4ABC-ACA2-663C5DA74C89.jpeg
Nothing plugs into that. The buttons in the bezel will work right away. You can add buttons to the screen via forscan but the bezel buttons will work fine.
The only pigtails you will need are the two wpt-1279 that connects between the second connectors in each seat.
The two wires you will tab for MS can +/- are pins 17 and 18 from the bezel connector, the one on the right in your pic.
I recommend not changing the sensor before plugging the seat, your sensor may already be compatible. If the light goes off, switch the sensors.
 
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Skywalker69

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Nothing plugs into that. The buttons in the bezel will work right away. You can add buttons to the screen via forscan but the bezel buttons will work fine.
The only pigtails you will need are the two wpt-1279 that connects between the second connectors in each seat.
 
 




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