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Old 04-03-2010, 12:48 PM   #1
Scooby Guru
Member#: 86459
Join Date: May 2005
Chapter/Region: Tri-State
Location: Campbell Hall, NY
2013 BRZ

Default DIY: How to swap an 08 STi steering wheel into an 05 STi

How to swap an 08 GR steering wheel into an older model sti (05-07).

This writeup is for an 05 sti, but i know the 06-07 cruise control is the same (i think). you can probably do this for an 04 sti as well if you mod the wires to work with an 05 and up cruise control stalk (

Before i start this, DO AT YOUR OWN RISK. I am not responsible for anyone else's car but my own. You are working with a explosive device and a dangerous one at that. TAKE YOUR TIME and double check EVERYTHING. do it right or dont do it at all.

ok, so...

before I start, this write-up wouldn’t be possible without the help of Dave (user name Nelly). He is the one who figured the wiring out, and id still be scratching my head in my garage right now if it wasn’t for him lol.

Im going to break this down into sections, if you see anything that is unclear let me know and ill go back and re-explain it. There is a LOT of stuff, and I might have missed something.

What you will need:
1) 08 sti steering wheel with buttons
2) PAC steering wheel control button unit (if you want the audio buttons…you need an aftermarket head unit to use this. I do not know how to wire this into a stock HU so please don’t ask me). The write-up uses the PAC SWI-PS. I do not know if the other models have different programming or wiring setups.
3) Balls for soldering
4) wire cutters, extra wire
5) 10mm, 17mm sockets
6) screwdriver
7) electrical tape

Removing your stock wheel
I don't have photos of this process, but this is easily obtainable on nasioc. i'll walk you through it.

Step 1 - pull on a flat surface and straighten your wheel as best as possible. Disconnect your battery and pump your brakes. WAIT 10-15 minutes (overkill but better safe than sorry) before attempting to pull of the airbag.

Step 2 - using a T30 Torx bit, break loose the two bolts holding the airbag from the wheel (the spot where you push for the horn for the dumb ). they are located on both sides.

Step 3 - carefully pull the airbag towards you. if it doesnt come out easily, you havent turned the torx bolts enough out yet.

For my 05 Sti, there was 2 things to disconnect on the back of the steering wheel:

1) the horn wire, just simply pull it off the metal tab it sits on.
2) the airbag wire. you need to pop up the yellow tab on the back (use a flathead), pull it out, and then pull up and out on the plug. set aside the airbag in a safe place.

Step 4 - unplug the cruise control harness from the roll connector. here is a photo of the roll connector, the green plug goes in the middle.

Step 5 - Get a 17mm socket wrench, and loosen up the bolt holding the wheel onto the hub. all i did was hold the wheel with one arm and loosen it with the other, it honestly isnt that tight (at least mine wasnt). loosen the nut to the end but dont remove it. your going to have to give the wheel a good tug to break it loose.

Step 6 - remove the plastic pieces around the steering column. i also removed the display surround as well for extra room.

Cruise Control

Be warned. If you are NOT comfortable soldering or modifying the circuit board on your newly acquired 08 wheel buttons, i suggest getting this done by someone else. there is little room for error and you can permanently screw up the board if you do no do this right.

Ok, so, now let me get into the hard stuff.

The 05 Cruise control harness (that plugs into the roll connector) has a green end, and has these color wires coming out of it:

green connector

Black: Cruise On/Off (pos. trigger)
Yellow/blk: Set coast (pos. trigger)
White/red: Resume accel (pos. trigger)
Yel/blk and wht/red: Cancel (pos. trigger)
Green/blk: 12v constant
Red: 12v switched

Cut the wires from the stock 05 CC. dont cut them too close to the green plug, give yourself some room to work with.

i didnt cut off the white plug on the 08 steering harness, i disconnected each pin. i suggest doing this, for i will explain later.

shot of white plug

before we get into everything let me explain the 08 harness.

Red: 12v Illumination
Black: Ground for lights
Yellow: Cruise On/Off (neg. trigger)
Brown: Ground
Green: Cancel, Set/coast, and Res/accel (neg trigger with resisters).
White: Audio signal
Blue: Audio ground

The signals for the cruise controls are different. The 08 uses 1 wire for cancel, set, and res. Where as the 05 uses 2 wires. the 08 uses ground signals and the 05 uses 12v signals.

shot of the circuit board next to the cruise buttons exterior. this is what you find when you remove the backing to the cruise control buttons. BE CAREFUL removing the back plate to get to the circuit board. i didnt snap out a peice before trying to pull it out and i ended up breaking a peice off

note: the photo below has two extra wires in it, for reference only for the backing of the circuit board. (these are wires that you have to solder in later)

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Last edited by xxscaxx; 04-04-2010 at 12:01 AM.
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