Heated seats retro install

[sal_park]

Hi,

I've been look to install heated front seats in my E34 for a while now and I'm finally starting to do it, just in time for winter :)

After finding this post (http://www.bimmerboard.com/forums/posts/135542) on doing the same thing on an E38, and after tim eh? (http://www.bimmernut.com/forum/showthread.php?p=310777#post310777) confirming that there is a good chance of a power loom already being there under the seat I though I'd give it go.
(edit: I've now confirmed power for the seats in my car :) )

I found a retro fit kit from WAECO (http://www.capitalseating.co.uk/productdetail.asp?pid=696) for ~60 GBP. I've now received this kit and it seem quite good quality (not tried it yet & no affiliation)

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Looking at the kit it assumes there is no switched live circuit powerful enough for the heating elements (max 4A each) so has a relay to supply this. Looking at the bentley it seems the only power to the seats (30A, F16 1 circuit for both front seats) is already switched with the ignition so I don't need to relay in the kit.

(Yes the little switches *do* switch the full power to the heated seats [shudders] )


Right, now I've got the seat out (http://bavtech.com/e34-guides/1995-540i-seats/front-seat-removal.php) and made it safe (http://www.bimmernut.com/forum/showthread.php?t=39661) it's time to start taking it apart.


Before we start, it's worth noting that my seats are sport seats which appear to be a different make up from the normal ones - all will become clear soon :D.

All the pictures below are my passenger seat (it's a right hand drive car btw).

1. Remove the seat back

The seat back is secured with two screws at the bottom. The screw heads are covered in little plastic caps which can just be levered off with a screwdriver. Below is the seat with these caps removed:
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screw close up:
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Once these screws are remove you can gentle pull the seat back backwards and outwards - the leather may stick a little, but constant gentle pressure will get it free:
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Now the bottom of the back is free the whole back can now be pushed up to completely remove it from the seat:
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(tear down continues here (http://www.bimmernut.com/forum/showthread.php?p=312092#post312092) in a reply later in this thread - image # upload limit reached)

[tim eh?]

good luck! i'm almost finished... everything you need to know is on that link for the e38(?) you posted. i had to repair the stitching too - it took me a while to find matching thread... and to stitch...

the pads just work on 12v you could hook them up to any switched circuit... the motors for moving the seat are on unswitched circuits but if you hook your pads up to those you'll kill the battery if you leave them on by mistake.

just so you don't do what i did, there is one tab (the ones under the seat you have to bend back to remove the leather cover) that i missed and the leather tore really easily when i first went to pull it off - the tab i missed was behind the hole that will be there after you remove the control box for the switches on the side towards the door - it's not bad you'll see but it could have been disastrous - don't miss any tabs!


here's a photo of the tear it's hard to see it's not so bad actually, testing the pad (the fabric seat is one of the ones i replaced) and a preview of what i did underneath - i had to either cut the old pad or undo all the stitching from the old pad but i don't think you'll have that problem if your seats never had heat - major headache for me but i had more problems... hope it works... for both of us!

http://www.bimmernut.com/forum/attachment.php?attachmentid=5988&stc=1&d=1222795270

http://www.bimmernut.com/forum/attachment.php?attachmentid=5987&stc=1&d=1222795270

http://www.bimmernut.com/forum/attachment.php?attachmentid=5986&stc=1&d=1222795270

[gmannino]

Thanks for posting, this is an upgrade I want to do when restoring my leather seats.

[tim eh?]

well... the seat is in and my butt's still warm from testing the seat... works A1++++ - i'll get some more pics up and try to write it up a bit... it works great looks ok but i missed a step (damn - i'll get back there one day). my main stumbling block was how to get the pad past the bar that holds the seams down that run across the width of the seat... i'm not sure how it will work on yours ... mine had the original pads sewn in it was such a pain. let me know if you're in a hurry or if you have any questions i was just right there!

it helps to soften the leather with warm water. also makes it easier to tear...

errr... yeah tiewraps work greeat just don't forget to attach the side bars too, or the middle section will bunch up like mine ... man i'm pissed i forgot that step but the leather was already stretched it was never going to be perfect anyway... it's all nicely stiched now tho and i managed to hide the tear i made!

cost me $3.49 for the thread.
edit- ...and a dollar for the tiewraps...
http://www.bimmernut.com/forum/attachment.php?attachmentid=5991&stc=1&d=1222892296

http://www.bimmernut.com/forum/attachment.php?attachmentid=5992&stc=1&d=1222892296

[Black 535i]

Great work. This is a good idea. I had mine apart last year to repair a tear in the leather and that is the easiest way to reinstall - using zipties. Just leave them all loose before tightening to allow for slack and stretching in weird areas. When all are installed, tighten seat base ones first and work towards the outer edges. Looks good and good luck.

[tim eh?]

Great work. This is a good idea. I had mine apart last year to repair a tear in the leather and that is the easiest way to reinstall - using zipties. Just leave them all loose before tightening to allow for slack and stretching in weird areas. When all are installed, tighten seat base ones first and work towards the outer edges. Looks good and good luck.

thankyou -i err yeah... i mean zipties... if i were to grade myself on this i'd give me a definite 'C' for the tear and forgetting the side bars but it's not the first time i've been happy with a 'C'... i'm mostly glad to have it stitched and the heat working - last winter was brutal i'd sit and stare at the switch when i was at stop lights :D

looking forward to seeing an 'A' from you guys...

[sal_park]

so now the back is off this is what we are left with:

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2. Unhook leather seat back

Now we need to bend back some of the tabs that hold the leather on. These are quite easy to snag your hand on :( so be careful !
I used 2 screw drivers - a big one (pictured) to leaver them out and a small one to get them started:

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It's very easy to slip so at this point I made sure the seat was not going anywhere:

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Now as I said above you only need to remove some of the tabs - in this case it's the top row and the bottom row - not the sides...well I did remove them first, just to see what would happen.... :D

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[sal_park]

3. Remove the hog rings

Now we need to remove these rings, as discussed here (http://www.bimmerboard.com/forums/posts/135542) in steps 17 & 18. There's about 20 of them and I bent them with two pliers to remove them. To make sure I don't miss any when I put them all back I've marked where each one as been removed with tippex, but I may be taking it a bit far :)

4 hog rings:
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Now with all the rings removed:
(you can see the tippex marks)
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Now we can remove the centre back - pull the top up:
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and push the bottom forward:
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and it should then pop out:
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[sal_park]

4. Remove the leather.

Now we have the centre back free from the rest of the seat:
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If we turn this over we can take the leather off of the foam. The staples come out really easily by hand:
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Leaving it like this:
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If we then turn it over we can see...more hog rings:
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Close up:
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[sal_park]

So after a few minutes all the hogs rings are now remove from the foam:
(I switched to snipping them first with some wire cutters at this point)

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And the back of the leather:

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Now we can start to line up the back heating element. The seat and the back are a different shape and I started by trying to fit the bottom element on the back :p. Anyway the size for the back element is pretty perfect for the seat, I've just trimmer about 10mm off the top and bottom so I can avoid 2 of the stitching lines as they are quite deep and I don't want to bend the element any more than I have to. As far as I can see the only restriction I can see is don't cut the cable :)
For the middle stitch line I've marked out where the holes need to go:

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Now we need to start adding the tie wraps. It's very important to have these all round the same way and uniform as it makes putting the leather back much easier:

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[sal_park]

No the holes have been cut for the tie wraps on the stitching line and the element has been taped to the foam (2 inch wide double sided tape was already attached to the element and it really quite strong)

So no going back now:
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Next thing is to put all the other tie wraps in place ready for the leather. Notice that they will all zip to the top of the seat so we can put the leather on from the bottom:
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First row losely attached:
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And then tightened and snipped so they are approximately the same size as the hog rings:
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And onto the next set. I didn't zip these ones up that much because I didn't want to bend the element tooo much:
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[sal_park]

Also for this row only I've smoothed off the cut end of the zip ties with sandpaper. If anything is going to break the cables in the element it will be a sharp edge here:
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And the last row:
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Now we need to staple the leather back to the foam. I used a standard stapling gun which has different shaped staples to the ones that came out:
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I'm not convinced that they will hold - I'll see how it looks tomorrow.

And finally, it's back in one piece really to be re-attached to the seat:
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I was quite please with how this looked pretty much the same as when I took it off and you can't see too much that the middle stitching seam is not a tight as the other two.

[tim eh?]

...looking great! quite a different seat than mine although the same principles apply to the job it would appear.

[sal_park]

So now we're onto the seat base. In order to start work on this we need the seat on it's side so we need to make sure the leather won't get damaged. To do this I've put a clean sheet of hardboard over the work bench and put the seat on that:

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The base of the seat needs first needs the tabs at the front to be bent back so we can unhook the leather. These hooks have 3 layers on and we only need to take of the first 2 (same piece of leather folded back on it'self)

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Yes, it is a totally different colour to the visible leather:
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Again we need to remove all the hog ties from under the seat - they are all visible but some are a little difficult to get to. Some of these go through metal sticks in the side bolsters - good to help you remember when you put it all back together ! Again I've marked the positions to try and make sure I don't miss any.

[sal_park]

Now we need to partically remove the under knee support at the front of the. Looking at the front of the seat you can see this clip:

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This clip needs to have one half lifted and then it can be slid off:

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With the clip removed the arm can be pushed out using a screw driver:

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You will not be able to remove the knee support yet ! This comes later on

[sal_park]

Now turning the seat back over you can lift up the back of the base, but it is still connected with 3 more hog ties:

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With these removed, the seat base is now free:

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And then the whole base can be removed by finally taking out the arm for the knee support:

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And now we have the seat with no base or back:

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[sal_park]

Now we need to remove the leather from the base - this is the same process as the seat back:

1 - remove staples
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2 - remove hog ties from stitching line
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3 - done ( in the words of Gordan Ramsey :) )
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I'm not going to totally remove the leather from the knee support as I can get to the foam area where the element will go quite easily as it it is.

[leicesterboy15]

Great write-up, keep it up! Its worth a go if the kit only costs £60! Doing a good job by the way, they look standard to me!

[sal_park]

Great write-up, keep it up!
Thanks, it's certainly been an education :)

So now we're onto putting the heating element into the seat base. Here it is lined up with no trimming:

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It fit's pretty well, but with a little trimming to move the wire of the element away from the stitching seam, and some holes cut for the tie wraps we have this:

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Finally we need to cut a grove into the foam for the cable:

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And now the element has been stuck in place with the tie wraps ready for the stitching seam:

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And now we need to flip it over and staple the leather back in place:

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BIG FAT WARNING: At this point I mucked up :p
I should have put the tie wraps in the leather before stapling it - see the details later in the thread on putting the seat back in for how to do it properly :D

[sal_park]

Now the seat base has all the leather back on it:

6124

We need to prepare all the tie wraps we can before installing it (apart from the missing one discussed in the previous thread)

On the leather is a metal pole the middle tie wrap must go around - it's easiest to install this before putting the seat base back in the seat:
(tie wrap is circled)

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And there are 6 tie wrap we can pre-install in the seat also - again these need to go around the metal pole in the leather. Ones that are highlighted in green go round the end of the metal pole in the leather seat base and need to be removed to get the seat base out. The ones hightlighted in red did not need to be removed at all because they are connected to the side bolsters only. (doh!)

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Now with a lot of effort (because I didn't pre-install enough tie wraps in the seat base) I was able to get the base back in and secured. The end result is fine (I think), but it would have saved lots of effort if I'd put the tie wraps in first:

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[sal_park]

And now onto the seat back. As before I put all the tie wrap in place for the side bolsters, i.e. the one's I didn't need to take out:

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And (unlike the seat base) I also pre-installed the ones in the seat back:

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Then it was a case of putting it back in and zipping up the ties:

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So the seat is mostly back together, the next item is to test it works and install the switch:

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[sal_park]

Now the seat was back together I connected it to a handy 12v supply and ... it worked :D

Now I need to get the switch installed. The switch is quite small and should just about fit in the grey push out panel above the seatbelt pre-tensioner. It's only 24mm across and the hole I need to drill is 20mm - not much clearance !. In the end I got it about 1/2 mm off centre, but it was still ok:

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Looking at the back you can see how close the hole is to the tabs (one of them was partly cut away, although you can't see in this shot)

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In addition to the hole I also had to cut a notch out for the switch:
(this was cut with a chisel - ug !)

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And finally the switch installed:

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[sal_park]

Now we need to connect the switch (I'll go into the wiring later on)

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and with a hefty shove it fits:

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Quick shot of how I routed the wiring under the switch. The wire going through the leather is the supply to the elements, while the other one is the power coming in. I needed to be carful here because the seatbelt pre-tensioner moves with respect to the seat base so I didn't want to wires to foul it:

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