996 Seat Disassembly and heated pad retrofit - My guide (996.2 Comfort Seats)

Hello, time for me to contribute something back to this community with this seat disassembly guide. This is going to be a long guide with many pictures so I'll just get on with it. This procedure is also useful if you are looking to replenish foam cushions or repair torn support nets. I believe 997 seat construction is very similar but don't take my word for it. Step 0.1: Tools and Materials ​ Heated pads (£25*2)​ To get maximum performance, you will need two sets, let's call them style A and style B . Style A, commonly found on eBay gives you independent wiring looms which we'll use to mount each switch to the seat panel itself, but the pads themselves don't get nearly as hot as style B. Style B (commonly found on AE) gives you one loom only (like if you wanted to mount the switched in the dash). You can differentiate between them by the pattern of the wiring and the style of the switch. I'm not linking a specific one, these are all the same generic stuff made in China and resold. We will use the Style B pads with the style A wiring looms. Style A Style B Hog Ring pliers & Hog rings (£16)​ After buying two pliers (the first one being useless), I have to strongly recommend the one from Gunson (Gunson 77128) which is more tailored towards upholstery than putting up fencing. Do not get anything with a thicker nose than this or an automatic, it won't serve. When it comes to hog rings, I made due with the Φ 2.0 the first pliers I bought from AE came with, but they weren't the best. Ideally you want something slightly smaller and C-shaped (these were M-shaped). 2 to 1 level nut wire terminals​ These are handy for connecting the positive lead while maintaining ease of seat removal. 20mm hole saw​ To cut out holes for the switches Existing tools​ - Pliers - Stanley knife & scissors - End cutters or robust snips - Spool of electrical wire - Trim tool Step 0.2: Seat removal​ I won't cover this in detail as it's fairly simple, lift tab and pull out rail guards (no screws on 996.2) then unbolt. Two finer points, 1. You do not need the E socket, a Torx will do without rounding, but having the E socket gave me more confidence using the impact to put the seats back 2. Although tempting, do not tilt the seat forward before you unplug it! The opposite is helpful actually, tilt it quite far back as it will be easier to handle the bottom cushion later.

Step 1: Removing backrest and bottom cushion​ The bottom cushion is fastened to the frame with two white clips at the front. Remove the center pin, then gently but firmly prize out the clip from the frame: Moving to the side, we unscrew the two small Phillips screws holding the switch panel and remove the height adjustment lever (leave the tilt lever). The panel is now held in by two tabs with hooked ends (see pic) so pull first up, then out to remove. Finally, undo the 4 plastic tabs holding the tilt mechanism to the switch lever and the panel can be removed. Gently pull the plastic frame outwards until it clears the height adjustment motor shaft: At this point the bottom cushion is only held in by two pins which slot at the back (mine was rusty and needed some tlc for some reason). Pull firmly and you will be able to remove it. Finally unclip the white wire connecting the frame to the cushion and off it comes Turning our attention to the backrest, there's two steps: At the bottom (backside), prize out the leather from its rail. Just pull firmly: Lastly, you need to remove the three white clips from the black rail at the top of the backrest. To do this, push in, then up when you feel them engaging: With that, we've removed both the cushions. Next, backrest pad installation...

Step 2: Backrest pad installation​ Begin by pulling the fabric in, around, and out of the white tabs all around the backside. The fabric tends to fray a lot leaving a couple of stubborn strands that block the tab from releasing so keep the stanley knife at hand. The 9 "windows" seen above are where hog rings attach the leather cover to the white plastic frame of the backrest. The foam is simply wedged between them. We will need to cut the hog rings. The below is what you'll be seeing as you peel back the leather to do this, there are three blue plastic rails with slots cut out where the hog rings attach to. Get in there with your cutter and snip these, peeling back the cover as you go up the rows. With that, the foam cushion is released. If yours is in need of replacement rather than just a vacuuming (it didn't look that dirty in person), porsche sells just the foam inserts for ~100 odd quid. Before I go on, I feel it's important to take a moment and explain heated pad construction/working principles. Here you see a pad with one of the fabric sides peeled off: There are two voltage rails on each side, one carrying +14V the other ground. The black thingy at the bottom is just a thermostat. So electricity travels from bottom to top in the picture via the thin strands of carbon fibre (which is the black weaved thingies you see, or at least...supposed to be, more on that in a second). This resistive load creates heat which in turn warms the seat. The question is, what/where can you cut this? Think of this as a bunch of mini circuits running vertically: - If you make a vertical cut as the one pictured, you only disable that row's heating capability. - Of course, you cannot cut through the rails , as this would prevent electricity from being carried further up than your cut. So any cut has to stay inside the lines of the voltage rails. - If you cut horizontally, you disable heating for every row along your cut (so you shouldn't do this). - The very bottom and very top (plain white areas with no wires), and the areas outside of the rails, are all fair game. Onto the hilarious bit... I'm showing a close-up of Style A pads but style B is the same. Our good friends the Chinese, to save a bit of money, make half the strands out of cloth which is of course useless. Only 1/2 or 1/3 of the black strands you see are actually carbon fibre/conductive/heated! I was flabbergasted when I realised. I guess this is done to amaze you with a nice tight weave. On the positive side, this means that when you cut slots into the pads, you shouldn't worry too much about losing heating capability, most likely you just cut through some pointless fabric Alright, back onto installation. Lay the pad onto the cushion, with its bottom end aligned with the bottom cushion slot. Feed the cable through the middle slot of the bottom row and out the back. Now trim the pad using the guidelines we established above, and cut slots at the locations of the two cushion slots using the Stanley knife. Bring the cuts close to the voltage rails but be careful not to knick them! Peel the cover off the sticky tape on the pad and stick it on. The cover can be a b...rd to get off as the whole tape wants to come off sometimes, the Stanley knife can be of help if so. Now it's time to put the leather cover back on, take some lengths of wire and use them to help you align everything. You should only focus on one row at a time beginning with the middle, as you need to put in the hog rings. Wire looped around blue plastic rail, in through the foam and out through the white plastic rail: Hog ring time. I'm not going to lie and say this is easy or pleasant, it has a learning curve, so don't be discouraged if it takes you a few tries to get them in correctly. The factory hog rings grab onto the foam as well, I couldn't manage to do so myself but it was not necessary. It's hard to take a proper picture but you will be looking at something like this while trying to put them in (picture is from the bottom cushion but you get the point) To verify you've placed each correctly, flip over the backrest and check the inside the "window" for the metal clip Once you've managed all 9, fabric goes back over and inside the plastic tabs, and wire gets threaded as such: That's it, backrest done. I just want to point out this is by no means a 50/50 job, the backrest is much faster and easier. It's silly but not a crazy idea to skip the bottom cushion install if you want to cut a corner. For the brave ones, onwards!

Step 3: Bottom Cushion Pad Installation​ Begin by undoing the clips at the back (see right side of photo), followed by the staples on both sides and prizing the leather out of the black tabs (center of image). Next, pull leather cover off the frame starting at the front cover. The leather is held on via means of a plastic rail in which the frame sits. Finally, with a pair of pliers, squeeze then push in the white tabs see in the photo (there's 10 in total). These pins have a learning curve, you need to squeeze less than you think and focus on pushing while pulling the leather cover from the other side. You can now remove the plastic frame. The orange net support is a common failure point I believe which you can replace. Another pic of the white plastic tabs, these move freely, don't worry if they fall out of their rail, just make sure not to lose any My bolsters were not falling apart, just needed a good vacuum. I also steamed the cushion because I read online that somehow helps restore plushness, I say that's total b cks, I saw 0% difference. But good to do for sanitary reasons I suppose. Now, onto the most tricky bit of the whole process. ​ As you can see, the pad is not wide, or long enough to cover all of the surface area so you have to 1. Decide to leave a gap at the front or at the back 2. Figure out a way for the leather cover rails to clear the pad and slot into the foam slots. I did my driver's seat like this and my passenger seat like this both are valid, the second placement is less work as you only need to cut two slots. Just lay the pad on top of the cushion, trim the bottom if needed and make your slots with the stanley knife just like before. Do not stick the pad to the cushion! The bottom cushion cover rails have metal rods going through them, so you cannot flex them to squeeze through the slot cut into the heated pad. Instead, I came up with the following procedure: 1. With the stanley knife, make 3 fingers' width cuts to the edges of each fabric rail. This now allows the heated pad to be slotted behind the metal rod (see picture). 2. Now, working at the same horizontal level, make a small "X" or "^" shaped incision outside of the voltage rail. This creates an opening for the hook at the end of each metal rod (see pictures below). This is to restore the tightness between the rod and the leather which we compromised with step 1. Step 3 (overkill). Still at the position of the rod ends, make a hole in the fabric on the side still attached to the leather and pass a zip through to tighten the rod end against it: The end result is a leather cover with the heated pad secured tightly against it. Sticky tape should be pointing towards the cushion side but with the cover still on. Now, take the white pins and 10 pieces of wire and thread a piece through each eyelet as such Working one row at a time, starting in the middle, use the wire to align the rail with the foam slot To secure the rod to the foam with hog rings, you will be looking at something like this: This will take some time and effort! I have a trick after going through what felt like 1000 hog rings that I hope might save someone some time: First create a "leading bottom edge" on the hog ring by priming it by pressing it with the pliers before putting it on. Next place the pliers so that the leading edge hooks onto the metal rail in the foam. You now have to negotiate the cover's rod around the top jaw of the pliers, but this is much easier as you can see what you're doing compared to hooking the top and blindly trying to get the ring around the bottom. If you've reached this point, congratulations, we're almost done. Time to get the leather+foam and attach it back to the frame. Feed each wire through the holes in the frame, and make a quick knot at each one as you go along to stop them from falling out while working on the rest: Once you've done this for all 10 clips, pull on the each wire tightly and the nose of each clip should peek through the black frame enough to grip it with the pliers. Warning: Resist the urge to pull the clip all the way until it clicks using the wire and use the pliers. Otherwise you will break the wire/ and or the clip's nose. If you break the nose the clip will no longer be able to lock. Just use the pliers. That's it, there's a few small steps needed to put the leather back on the frame, but "installation is the reverse of removal" applies here.

Step 4: Installing switch + wiring​ In my opinion the switch should be installed the position causing the least stress to its soldering. Due to construction, this means placing it as such: so that the wire feeds out from the switch panel and towards the middle of the seat at no angle or a very slight one. Sorry I'm doing a terrible job of explaining it, but if you demo it it will make sense. This hole actually needs to be 21mm, but as that's an unusual diameter we can make due with 20mm+ some filing/dremeling. Finished look: Regarding tidying up the wiring at the bottom of the seat, not much to say, except..before putting the bottom cushion back on, triple check all the wires are routed like they're supposed to. The first seat I did I had to remove and reinsert the first bottom cushion three times, and for the second seat, having learned my lesson, you guessed it, only two. When it comes to wiring, the other benefit of this wiring loom is that it only requires a positive and a ground (others might need constant live, ACC, and ground). The ground is easy enough, there a grounding point underneath each seat. For the positive, I do not recommend tapping into a constant live for obvious reasons. Instead I found an ACC live by probing with a multimeter. On the driver's side there an ACC in the main seat harness (the blue, shown here is the corresponding female in the seat connector) On the passenger side I didn't have this, but I found an ACC going to the parking assistant module. There should be more as you also have the immobiliser and alarm control unit there but I wouldn't mess with that. Anyway the ACC is the black-brown wire seen here (don't rely on wire colour as it may differ from MY to MY). Once you find your ACC, put one of these bad boys in (rated for much higher amperage than the heated pads draw) and bob's your mother's brother! Extra resources: This is great video on the topic overall: but it has some issues (like claiming you can't cut the pads, you can, just follow the guidelines from my previous post) which inspired me to write this. Also credit to this video (I think the author is a member here) for the wire trick:

Correction regarding the driver's side wiring: turns out that ACC wire in the buckle pin cannot carry enough current to warm the seats. Solution: use a fuse tapper on fuse A6 (heated seats fuse), there's an ACC line in all cars there.

This is awesome - thank you!

Great, bookmarked for future project

Great write up is it possible to retro fit the oe setup?

outstanding @Dovoda75

Quotes source post: 2760137

@Richie N it's just a switch you need in the end, all of the above and then wiring into the OE switch panel

Does the OE switch have 2 settings?

Nearly a year in and these are still awesome. In fact the thought of losing them makes it hard to pull the trigger on aftermarket seats like Nogaros or Pole Positions or 997 seats Also just looking at my post I am once again reminded the biggest lie we tell ourselves is "I'll remember how I did this" I would be totally lost on some steps if I had to do this without my notes here to go back to

I agree, the number of times I have referred to my own videos on YouTube is surprising MC

Quotes source post: 2760392

It does in that it is on or off. MC