The Long Awaited: The Myth, The Legend, The Douchebaggery

[SlimKlim]

My car came from the factory with the black "Vader" seats. People are crazy about the things, and they do look cool, but that's really about it. The bolsters are way too far apart for anyone who could be considered skinny, the headrest is completely non-functional, and my particular set had 16 years of absolutely zero care or attention, and the driver's lower back was shaped like a C.

I could've replaced them with a mint set, but because they are so popular with enthusiasts (particularly black ones) I would be looking at $1200+, and still had no bolsters or headrests. Instead I went for a set of E46 M seats I was able to get in above average condition for $500. They also have heat, lumbar support, and adjustable bolsters. 8)

However, this means I have to run power to the seats, time to party.

Label your wires!



I like to take a few minutes to do this, pouring over wiring diagrams requires most of my brainpower, and stopping to squint at one while wrestling with a 90lb seat is never fun.

The seats I got had the later style E46 connector, which was one monster 24 pin connector that ran all the wiring to the seat. However, you can disassemble the connector and it falls apart into several different plugs, and becomes much easier to work with.

Here's my basic plan/schematic:

The 12 or 14 gauge red/brown wires are power and ground for the entire seat. My plan is to pick up the factory wiring for the power seats at the fuse box, and ground them to the body under the seats.

The K-bus wire needs constant power to make the memory controls work. I'll just tap it to the power supply for the seat, its also constant.

The occupancy sensor and seat belt switch will be spliced into the E36 wiring. The rest of the E46 wiring will be unused.



Speakers in your garage are almost a necessity. I started by taking out a good bit of the interior.









Removed the kick panels, sill trim that goes over the edge of the carpet, and undid the bottom seat belt mount so I could slip the carpet around it.

I also pulled the center console, and since the rest of it was out anyway, my roommate pulled the glovebox and changed my cabin air filter for me.



Making my ground wires. I used crimp on ring terminals and quick disconnects, and heat shrink to insulate them.



The idea to pick up the factory wiring fell apart. I could understand the wiring diagrams to know which fuse to use, and where the wire ran from the fuse through the firewall, but I couldn't read it well enough to know where to pick up the power supply to run into the fuse.

On top of that the two rear most screws in my fusebox are stripped and seized, and they are buried down between the box and firewall, so I've tried and failed to remove and replace them in the past. I decided to fall back on another method other's have had success with. After a quick trip to the store to pick up some inline fuse holders to install in the power wire under each seat, the show goes on.

The circuit for the cigarette lighter also uses a 30 amp fuse, so you can tap the seats directly off it. I can charge my phone through my head unit, so I never use the cigarette lighter. I decided to completely disconnect it, because I want to minimize what can be run on my new borrowed power seat circuit. I split the connection here (solder and heat shrink and bundled with electrical tape) and ran it under the console, then under the carpet on either side to the floor pan.



Dremel again, I have to trim this cover a little to make room for my ground wires.



Ran my ground wires to a body nut under the seat. I used a ring terminal and a washer, then the factory plastic nut.



The power wire run under the carpet



Testing my ground with a multimeter, always a good idea, that way I know I have power if the seats don't work.

Then i added my inline fuses and put a connector on the end to connect to the seat.



Might as well get some vacuuming done.



With all the necessary wiring run under the carpets, I put all the trim and console back in the car. It's a lot easier to do with no seats in the car.



My wiring. After this photo I realized that the bar I have them ziptied to rotates, so I had to bundle it with some of the wiring on the seat instead.

I used a 12 G quick disconnect with heat shrink over it to insulate it, and then electrical tape to cover the small gap, don't want anything getting too friendly and shorting out. Surprisingly the seat belt switch wiring plugs right into each other, and the occupancy sensor on the passenger's side also plugged right in.

The driver's side of the car's wiring has a wire that runs to the "seat belt warning lamp" which has never been functional in my car. The light works, I see it when I turn the ignition on, but it goes off as soon as I start, regardless of if my belt is fastened. I wonder if E36s are equipped with that feature but having it function wasn't a hard requirement in '95. Or my car was dropped on its head as a baby.

With everything plugged in I put a fuse into my inline holders and tested the seats. Power!

I started the car and watched the airbag light. It didn't turn off immediately after it started, like it is supposed to, but all is not lost. My airbag light has stayed on for ~3 minutes after I start the car ever since I got it, it will still pass inspection and the code says occupancy sensor, which is a common issue and doesn't disable the system.

I waited for 3 minutes and the light went off, I guess borrowing the E46 sensor didn't do the trick, but it also didn't throw a permanent code, which I half expected to happen.



I test fitted the seats. The brackets are extremely close, but need some fine tuning before the bolts will go down in the rear. They need to come forward about 1/4in and the inner edges of the holes need to be ground out a bit. Back to the dremel.

I took some material off the rear of the front holes, and and some off the front of the rear holes to spread out where I was removing material.