EU Spec fully electric rear seats retrofit...

[IT]

I am making small in roads into this project still, but its taken a back seat (pun intended haha) to the RNS-E install that I need to complete in parallel.

Once the RNS-E wiring is all in place, then I can finish the wiring for this, sort out a few engineering challenges and actually start to put this thing back together....

I do have a few updates, but they dont mean much without photos, which I dont currently have, so I'll leave you in suspense....

[Oli18]

Hi Ian - fantastic amount of work you've put into this. It is going to be 1 of a kind by the time you finish.

[IT]

Originally Posted by Oli18

It is going to be 1 of a kind by the time you finish.

I know....I confess, I am starting to feel a little smug....

[IT]

A few updates - Given the weather, working and babies being born, progress is an hour at a time here and there at the moment, so its not been worth an update in the past few days, but now I've got a little further, then here we go:

One of the pending items has been to install the extra switchgear. My car was 'poverty spec' with hardly any options, so I needed to add the blinds switch in for the rear blinds that were fitted, and I also need the switch in for lowering the electric rear head rests.

Both switches require independent connections to the rear of the car to do their job, but also require connections to a suitable ignition feed for the +12 for them to work, and also a connection for illumination. As the car was mostly apart, I removed the whole center console, stripped the wires back and connected these in as far back as possible, re-taping up afterwards. The result? Factory looking cabling, and here we have a quick test to see the illumination working, so I must have 2 wires per switch correct anyway



My second problem swichgear is the rear seat heating. These switches are a pain as they are out in 'no mans land' as far as wiring is concerned. No wiring runs over the tranmission tunnel between the rear center vents and the rear seat, so tempting as it is to go directly across there, I have avoided it and gone all the way round instead. This also enabled me to pick up the relevant illumination feeds too on the way round, and again a quick check here once all done:



One thing that has become clear in this project is understanding how something is supposed to work, only then does it become clear how to wire it up. The wiring diagrams are great logically, but physically routing through cables is a whole new ball game. A test meter has limited use too as so many wires are +12, some of the time. But when? For examples, switchgear only illuminates when the lights are on, fairly obvious, but the rear seat auto-retract only works when the relevant rear door is open. The passenger seat in the front only moves from the rear if the drivers isolation switch isnt pressed. The blinds only work with the ignition on, but the rear seat heating only works with the ignition on AND someone sat in the seat.... A nightmare really, but I think I've got it all sussed.....

Here is a shot of the back of the car at the moment. 95% of the interior wiring is now home and in place. I've got a few ground connections to make, and the spaghetti in the center of the rear seats to shorten and neaten, but apart from that the front end is all in place.



The power for the rear seat electrics, and rear seat heating is independently fused from the distribution board at the rear of the car. I have also decided to feed the rear blind supply from here also. From the factory, the blinds would be fed off an independent fuse down by the drivers footwell, and to be honest it was just easier to run it backwards to here, rather than forwards all the way down there, so I now have 3 wires popping out in the rear that will need hooking up to provide juice. Other items that connect here are the Audio system and towbar power (where fitted)



Back to my engineering problem of 4 bolts and only 3 threads for the rear seat frames, I've finally got this one in the bag.

The original Audi seatbelt bolts were some rediculous thread, 11.127 x 1.17 or something equally unrealistic, and this was a stumbing block for a while. I wanted to keep to the original Audi design spec for bolts / threads where possible, especially where safety was involved. Finding this size tap though was going to be impossible.....

.. or so I thought, it turned out to be imperial, a 7/16" UNF thread to be precise, so once I'd tapped my ally bars with that thread my original Audi seatbelt bolts now fit perfectly. The bars will slide inside the original holeand brace up against the body. The more I tighten them, the tighter they will get....



How it will sit, and green circle marks a wad of earth wires I've yet to mate with the chassis...



I've only got one other snag at the moment, which shouldnt be too hard to overcome, but the airbag wiring for the individual seats is a completely different colour to my factory wiring. Being the suspicious chap i am, I've checked into it and its not an individual seat thing, but more of a model year thing. Early facelift cars (mines a 1999) have different Airbag wiring looms to later ones, which is what the donor car was. On checking further, there is a later version of the airbag module used on later cars too, so I'll be changing that over as well just to be sure.

So, items left to do:

* Shorten / sort cables in rear center box
* sort ground cables
* swop airbag module
* wire up airbags with new cables
* drill out the old seat hooks
* connect up the rear distribution panel in boot
* Double check, insulate / tape all wiring
* pop the rear seats in and test it all works
* put it all back together......

[gninnam]

Phew! - a good read so far Ian

[IT]

Originally Posted by gninnam

Phew! - a good read so far Ian

Thanks & Wow... people are still reading... Even I'm starting to find it a bit drawn out now, but there is light at the end of the tunnel..

[r8dream]

really great pics and read ian, i always retrofitted electrical options in my cars since i was 16 yrs old.
now yours looks fit for the queen in the back.
i met prince charles a couple weeks ago and got to chat about his aston db6's engine rebuild to run on ethanol, new high comp pistons.
oh and congrats on your new arrival, i've got 3 myself, can't wait for more.
that color leather looks more white than my beige, is it ecrue or platinum. it suits my s8's blue better.
i am looking for a set of s5 seats in ivory for mine. john

[IT]

Thanks John - Yes its a platinum interior, light grey in regular 'non audi' speak - It was the standard grey pre-facelift, then at facelift the more common grey became swing, which is a darker grey....., and the platinum colour became more common in 2002 with the final editions, and many of the other cars built around that time....

[IT]

Well, what a great day......

I've got loads finished off today:

All grounds are connected
Airbags are wired up
Old seat hooks have been removed (green arrow)
New seat rollers are installed (Red arrow)
All wiring to central seat box is now present, cut to length and good to go (blue circle)

I did changeover the airbag modules, but a quick vagcom check suggested that it wasnt as happy as I would like. It complained lots about the seats that were all missing, which is fine, but also complained about stuff that should be working. I decided instead to stick with my original controller, and code it for no center rear seat belt tensioner. The only modifications I've had to make to the airbag wiring it connect the 2 airbag ignitors in the side of the rear seats to the connections from the airbag module. The donor seats come from a 2001 car, so they dont have occupancy sensors to decide whether a seat is occupied before deploying the airbag. To get round this, I also coded my module to ignore the absence of the rear seat occupancy sensors.

Interestingly, on a slightly related note, the rear seat heating normally only works when the seats are occupied. In 5 seat cars there is a mechanical switch under the seat which gets switched when you sit on it. With a non-fixed base, this wont work, so instead the seat heating will only work when the seatbelt is fastened as the contact for the seat heating runs through that.....

The old seat hooks came out reasonably easily, once the heads were drilled off the retaining bolts from the boot side.

The new rollers went in really easy too, just 2 bolts a piece.

Whilst its not so easy to see from this photo, all the wiring for the reat seats are now in place, I just have to plug in the +12 feed in the boot, which I've not done yet just to keep things electrically isolated. Its all in place, taped down, clipped, secured or whatever it should have been originally.



I've also vacuumed out the whole car insides, which along with the carpets that have all been washed with a wet vac, things should look pretty clean once I start the re-fit.

Next job is to pop the rear seats in, hook up the +12 and double check it all works. Assuming it does, I just need to pop in the rivnuts and bolts to secure the armrest, and then the interior refit will commence full speed

[Oli18]

How does your wife allow you to spend so much time on this? lol! I'm trying to find time to fit the exhaust and rear brakes, let alone do what you're doing.

I can't wait to see this in the flesh! ... it really does look the business.

Oli