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I have driven 140k km in my 2013 Model S and could not pass on the opportunity to upgrade the seats all the way from Gen1 to Gen4 which came from a crashed 2019 car.

I picked up a complete set of flawless 2019 seats, including rear and door panels. These seats are vegan and have the adjustable headrest.

Note: It is possible to connect the headrest, but I did not go the extra mile for this.

You may also find that some of your wires have a different color compared to this guide. The best thing to do would be to match the pin layout of the connectors if that's the case.

Swapping the rear seats are pretty easy. The hardest part is removing the plastic clip that holds the bench. I do recommend getting a new pair of these from your local service center in case they brake. They are around $1 each and there is two for the bench and two for the side bolsters. I actually recommend not clipping in the bolsters in case you need to remove them again. I could not for the life of me figure out how these clips worked. I jammed a screwdriver under the bench and when I could feel that I hit the clip I pried until it popped loose.

The bench is then loose and you can remove the connectors that are attached. When removing the rear backrests you need to undo the black bolts and you should be able to remove them from the car. When installing the new seats you need to transfer over the old black bracket to the new seatbacks or else it will not fit, trust me. 

When the brackets have been transferred the new seatbacks slide right in and you can bolt them down again.

The new bench has the occupancy sensor integrated into the seat rather than fixed to the metal frame like the old bench. Therefore you need to move over the connector to unplug these white square pads shons below and plug them into the seat instead. The new seats have identical pads.

You do not need to remove or modify the metal frame in any way. New seat is plug and play. Does not require any config either. 

Now it's time to start working on the front seats. I chose to start with the passenger side as it has less wires (no memory module) and I could still drive the car.

This does not require any config changes to the MCU and you don't need to pull 12v because it does safety check every time car goes into Drive. If wired correctly faults will not stay and are not necessary to clear. There is no danger of airbag suddenly going off, but always be careful.

Remove the rail covers on the front of the seat. These just pop right off. 

The bolts towards the center console is Torx 47, a very unusual size. It is recommended to acquire the right bit-size, but a Torx 45 bit will remove the bolt without destroying it. That's what I used.

I highly-highly-highly recommend using an impact driver instead of a breaker bar or ratchet. Using a manual tool may cause unwanted wear on the torx pattern. These bolts are pretty tight and can be difficult to get loose. When using an impact driver, don't be afraid of letting it work a little, but be careful on the throttle and observe if it breaks the bolt loose or is chugging away at the metal.

The bolts closer to the door are actually a smaller Torx 40, a more common size. Again recommended to use impact driver.

When the bolts are out you can just disconnect the airbag and main wiring going to the floor of the car.

To get the seat out I just folded the rear seats and removed the parcel shelf. I then carefully twisted it out of the trunk. Can be done alone, but easier being two.

Find a good working surface where you can have both seats side-by-side and be careful not to scratch or damage the seats when working.

There is a cover going over half the bottom of the old seat. This is just clipped and strapped in. Undo it to reveal the bottom. The side plastic pieces are screwed and clipped on. Make sure you remove the screws (2 on each panel) before prying off. This will reveal further wiring. Also be cautious that wires are attached to this panel.

Then start unplugging all the connectors to the various motors, switches and light.

I advice you to take pictures of each connector you remove so that you know where they go on the new seat. Most connectors are actually plug and play!

Now the bottom harness should be completely free. You may need to cut some zip ties or other mounting solutions. Remove harness from seat.

The remaining wires you can see are:

• Bottom heatpad

• Rear heatpad

• Recline-motor

• Lumbar left and right

The little box at the bottom is the heater ECU for heated seats. You need to remove this as well as we are going to re-use it in the new seat.

Note: The new seats heating pads run off 12v and this ECU only provides 6v. Therefore there will be half the heating power. However, I think we all can agree that running the old seats on 3 bacons got uncomfortably hot unless you are sitting on snow on top of the seat.

I know of one person who successfully moved over the old heatpads. I just used the 2019 pads with the old ECU and it has been fine.

Now you can cut off the wire and connector running to the heatpads. I cut it about half-way. This is because we are going to re-use these connectors in the new seat to make them fit the old ECU.

Now you need to pry up the bottom of the seatback. This was insanely difficult due to the clips used so don't be afraid to use force.

I was unable to get it anymore loose than this. You may have better luck, but when I was standing on the seat and pulling with a lot of force and it wouldn't bulge so I just gave up. I then cut the wiring to the recline motor because it was so hard to unplug.

I then started working on the new seat. I first unclipped the bottom cover which is strapped on. I then removed the side panels. These are mostly held on by tight clips, but there are also one screw on each side that has to be removed. When the side panels are removed I disconnected the connectors. 

This is how you connect the old air bag connector to the new seat

I then started unplugging everything from the old seat and started connecting the old harness. Most stuff is plug and play, but some require some modification.

When removing the seatback on the new seat, you need to insert a trim tool at the very top where the headrest is and then pry. You then continue prying until the seatback is completely off.

Lumbar: 

Pink&white to green&yellow

White&brown to red&blue

Yellow to green

Pink&white to blue

Seat sensor:

Yellow to white/green

Pink to purple

Recline motor:

Purple to orange

Pink to yellow

White to black&white

Red to green

Heat ECU:

Black to black

Black to green&yellow

Purple to red

Green to gray

Red to gray

Black to black

Now you should have everything connected in the new seat and you can put the non-controller side panel back on and put the seat into the car. I cleaned up the wiring and made sure it looked neat under the seat. Also make sure that everything has a little slack due to the seat movement.

I then removed the controls off the new side panels by removing the screws on the back and then using a trim tool to pry off the buttons.

I then used a dremel and drill to cut out the hole for the old seat controls. I used a piece of paper on the old side panel to draw a template and then used that on the new side panel to make sure I had a guide. This takes some time in order to make it nice so be patient and don't overcut it. I then used Tec7 and let it dry for 24 hours and the result looks great. I then put it on the seat. Remember the one screw.

Also, make sure you test every single function in the seat before you put on the backpanel. Those clips suck to work with so you really don't want to take it off again.

The driver side is mostly the same besides the memory modules. You just move these over to the new seat as well.

Let me know if you run into any issues! I think I have covered everything in this guide, but I might have missed something.