Connecting 20-pin Harness To HU's Harness
Read and understand all of the connections before
starting. You will be joining the +12V and ground wires from
several different harnesses (my 20-pin, your HU's, ASWC, and possibly
See this guide for connecting my 20-pin Subaru installation harness to your HU's power/speaker harness.
Connecting the ASWC Module
Refer to my pin-out table for Subaru's 20-pin harness. Column "A" shows the wires on the 20-pin harness.
Ignore the printed "Application Chart" booklet that was included in the ASWC package — some versions of the booklet have incorrect diagrams and/or pin information for the factory harnesses in Subarus.
Also ignore where the ASWC vehicle-specific docs talk about connecting to your Subaru's factory wires. You will use the two or three SWC wires on my harness (which are BROWN/RED, BROWN/BLUE, and BROWN/BLACK).
Connecting the ASWC to the Car
Note: If you have either the OEM Kenwood or TomTom navigation HU, I also build a 24-pin harness that will allow you to connect to your car's SWC wires without splicing into the factory wires. E-mail me for details.
2008-up Impreza, Forester
2010-up Legacy, Outback
(click to see larger images)
Do not ground any of the ASWC's other wires.Note: The ASWC's harness originally had both GREEN/ORANGE and ORANGE/GREEN wires. Several people have used the wrong wire, so look closely at yours. The stripes are thinner than the main color. On the GREEN/ORANGE, the orange was pale (somewhat washed out).
Your ASWC module must have firmware dated July 19, 2010 or later.
2010-up Legacy, Outback w/ BT
(click to see larger image)
The ASWC's 12-pin harness will have several "leftover" wires that you won't use. Individually insulate all of those unused wires on the ASWC's harness. Don't cut off any wires — you may need them if you want to re-install the module in another make/model car later.
Note: The pink wire on
the ASWC harness may be labeled "MUTE". Ignore that label — this wire
has nothing to do with muting (Metra's harness subcontractor used pink
wire labeled for radio harnesses).
Most HUs have a 3.5mm jack for wired steering wheel controls. For those, simply plug in the ASWC's right-angle 3.5mm plug.
Eclipse, Kenwood, and some recent JVC HUs have plain wire(s) instead of a 3.5mm jack. For those, you will use the 3.5mm jack adapter that was included in the ASWC package. Follow the directions in the ASWC's instructions for connecting the ASWC adapter's wires to your HU's SWC wire(s).
Metra recently started including a tiny 12K ohm resistor in
each ASWC package. I insert that inside the plastic bag with the
ASWC's female 3.5mm adapter. If you purchased your ASWC from
someone else, you may find that resistor loose in the package or folded
inside the warranty card. See my notes about the resistor, below.
Tip: If you don't need the ASWC's 3.5mm jack adapter for your
install, save it in case you later switch to a Kenwood, JVC, or
Eclipse HU. I suggest wire-tying it to the ASWC or its
harness, to store it behind your HU.
Instead of a 3.5mm jack, Kenwoods and some recent JVCs have a single wire for "Steering Remote Control" on the power/speaker harness (normally LIGHT BLUE/YELLOW — check your HU's installation manual to verify the color!). Connect as follows:
Instead of a 3.5mm jack, Eclipse HUs have two or more individual wires. These wires may be part of the power/speaker harness, or on one of the additional harnesses that plug into the rear of the HU. The opposite end of the SWC wires may terminate into a white, rectangular, 20-pin socket.
Some Eclipse HUs use BROWN and BROWN/BLACK wires. If your
Eclipse uses those colors for its SWC wires,
connect as follows:
Other Eclipse HUs use wires colored BROWN, WHITE, and BLACK.
If your Eclipse uses those colors for its SWC wires,
connect as follows:
If the HU does not recognize all of the car's SWC buttons, try
reversing these two wires.
If your Eclipse HU has different SWC wire colors, and the HU's installation manual does not identify them, you will need to contact Eclipse and/or Axxess technical support for guidance.
The ASWC will automatically detect the Subaru's wheel buttons. You do not need to press a Subaru's Volume Up button during detection. In most cases, the ASWC will also automatically recognize your HU. Simply follow the ASWC's normal procedure for auto programming.
Since many HUs don't support any of the phone/Bluetooth
functions, when the ASWC detects some certain HU brands, Metra opted to
have the ASWC default to assigning the car's phone buttons to do audio
functions -- preset up, preset down, and mute/ATT. If you find
that is the case for your HU and you think the HU might support the
phone commands, you will need to program those buttons.
Metra recently added a shortcut step to program the phone functions: After the ASWC's auto programming completes (and after it gives the LED blink codes to confirm which wires and which HU brand are connected), the LED will go solid RED. Press and hold your wheel's on-hook button until the LED turns off (should take about 4 seconds). That should program all 3 phone/BT buttons. Test to make sure all 8 buttons work. See ASWC's vehicle-specific guide (online) for more details on the shortcut.
On cars with phone/Bluetooth SWC buttons, the ASWC module (as well as the modules from PAC Audio) will definitely "see" all 8 of your car's SWC buttons (including the phone/Bluetooth buttons). You can program the module to assign each button to any remote command that your HU supports.
That last part is key: Many HUs don't have remote control commands that correspond to all of your wheel's phone buttons (even HUs that have built-in BT). This is usually a limitation of the HU itself, not the interface module. HUs where the BT function is provided by an external accessory unit have been especially bad about not recognizing those remote commands. You can program the ASWC to assign any leftover buttons to do additional audio functions (e.g., Mute, Band, Seek Up, etc.), so none of the buttons need be "dead."
If the ASWC's automatic programming appears to leave the phone
buttons (or any of the others) unassigned, first check your wiring (see the
"troubleshooting" tips in the ASWC's manual, and check that the LED
blink codes match the wire colors you should have used). Next,
try the ASWC's manual programming procedure — assign the "dead"
buttons to other audio functions that the ASWC didn't choose (e.g.,
Band, Preset Up/Down, Mute) and verify that every button works.
That will at least confirm that the ASWC is able to see all 8 of your
Once you've verified that the ASWC is able to see all of your car's SWCs, you can try manually programming the three phone buttons to do the corresponding phone commands. Several people have found this works, even though the automatic programming did not assign those buttons. For any buttons that still don't work, you can again go back and assign those to do extra audio functions.
The ASWC is detecting some recent Kenwood HUs as JVC. The two brands are now owned by the same company and are apparently sharing some circuitry. Metra's instructions now say these Kenwood models exhibit this problem: DNX9960, DNX7160, DDX896 and DDX418. You can solve the problem either of two ways:
Remember that the
ASWC's reset button is inside the hole
towards the left (closer to
the USB port cover). If you need to press the button, use a blunt probe (such as a toothpick,
small hex key, coffee stirrer, paper clip, stem of a Q-tip, etc.) and
insert that into the hole.
The hole towards the right
(closer to the harness connector) has the LED underneath. Don't poke
anything in there!
The ASWC's USB connector must NOT
be connected directly to a computer's USB port — you will fry the
ASWC module. Metra's USB-CAB interface cable converts USB to +5V
TTL serial. Their
updating software will only work with certain converter cables.
If you need to update your module's firmware, I have the USB-CAB cables
The latest versions of the ASWC product manual and vehicle-specific instructions are available from their web site. Always navigate from their home page, to be sure that you get the latest version of each document.
Be aware that Axxess may post revisions to these documents "in
place" (without changing the file names or URLs). So it's not
easy to tell when a file has been updated. You can check the
"document properties" in a PDF to see the "Created" and "Modified"
dates (which are different than the date you saved the file to your
Start at their home page: www.axxessinterface.com
In the Product Browse box, choose "OE Integration - Use OE Steering Wheel Controls with New Radio"
Under Products, click on Axxess ASWC
This brings up a link to a PDF doc for the Product Instructions.
From Axxess site's home page, in the smaller box on the right
side of the page, click on "Steering Wheel Control" to go to this page:
Select: SUBARU, (your model), (your year), and your factory radio (e.g., "WITH STANDARD AUDIO SYSTEM", "WITH NAVIGATION EQUIPPED AUDIO SYSTEM", etc.).
This brings up a list of the car's factory wire colors and pin numbers, and a link to a PDF doc for the vehicle-specific installation instructions. Beware: Some of those PDF files may still show incorrect harness diagrams and/or pin numbers.
From the Axxess site's home page, in the smaller box on the right side of the page, click on "Axxess Updates" to go to this page:
There you'll find a blog with release notes, as well as some
© Copyright 2010-2012 by David Carter. All rights reserved.