Parts Needed
to install an after-market Head Unit
2011-up Impreza, WRX, STI, OBS,
Forester, Crosstrek
with phone / Bluetooth buttons on steering wheel

For Impreza and Forester models without phone/Bluetooth buttons on steering wheel, see this page

When you place your order, let me know you've seen my "Parts Needed" page.

Wiring Harness

For all of the above models with Bluetooth (i.e., steering wheel includes Off-hook, On-hook, and Talk buttons), you'll need my 20-pin "forward" harness with 3 SWC wires ($12).  Link.

You'll need to solder or crimp my harness to your new head unit's (radio's) power/speaker harness, creating an adapter that is mostly "plug-and-play."

If your Subaru is a 2012-up Crosstrek or Impreza (not WRX or STI), or 2014 Forester, your factory radio harness includes a wire for the Vehicle Speed Signal (VSS).  A few aftermarket navigation HUs can use this signal.  If your new HU needs it, I can include a corresponding wire on my harness for an additional $1 ($13 total).

Steering Wheel Interface Module

The SWC wires on my harness are only part of the solution — that saves you from needing to splice into factory wires.  However, most aftermarket HUs also require a steering wheel interface module — either the Axxess ASWC (by Metra), one of the various SWI-* models from PAC Audio (SWI-PS, SWI-JACK, etc.— different models depending on your new HU's brand), or iDatalink Maestro.  More people prefer the ASWC.

Many Subaru owners have installed ASWCs and given rave reviews.  In most cases, it programs itself and is ready to go a few seconds after the first power up.  You can also manually program it if you want to reassign any buttons.  Installation is much easier than the PAC modules.

I have the ASWCs available.  See .

Retain Factory USB Socket

Your factory HU has a socket on the rear for its USB input.  A factory harness connects from there to the back of the USB socket in your armrest center console.  That harness has proprietary plugs at both ends.  The harness only handles the USB socket — not aux.

Metra now makes a plug-and-play USB interface cable for Subarus, their AX-SUBUSB.  This connects between the car's plug (that is/was plugged into the back of your OEM HU) and your new HU's rear USB socket.  Picture, picture.  BTW, the length of the cable is actually 18" between the two connectors (not 2 or 6 feet, as some sites say).

I have those available for $12.

Note: 2014 Forester switched to a Toyota-style USB connector.  I now have those, also $12.

Retain Factory Aux Jack

Your factory HU has a socket on the rear for its stereo aux input.  A factory harness connects from there to the back of the 3.5mm aux jack in your armrest center console.  That harness only handles the aux audio connection — not USB.

If you want to retain use of your factory 3.5mm aux jack, I make an aux adapter similar to this:

Subaru 16-pin aux adapter harness with RCA plugs
(click thumbnail to see larger image)

The white 16-pin connector fits the end of the factory aux harness behind your OEM HU.  My harness retains the stereo aux jack only, not the USB.  Price for the aux harness as pictured is $22.

Although I have a version with a stereo 3.5mm plug in the works, currently I'm only able to build these with male left/right RCA plugs (as pictured).  If your new HU only has a rear 3.5mm aux jack, you can use a short, inexpensive RCA to 3.5mm adapter such as this.

If you're planning to connect an iPod or iPhone, many recent HUs use an iPod interface cable which splits out into two plugs at the rear of the HU — one to plug into a USB socket and the other into an A/V aux input (4-pole style, with both audio and video).  Your car's factory 3.5mm aux jack supports stereo audio only — it will not support video for an iPod video cable.  So if you plan to use that kind of iPod cable, you may not want my aux harness.  See this post for pictures and more information.

None of the Pioneer AppRadio models has an aux input.

Retain OEM Subwoofer

If your car has the rectangular-shaped OEM subwoofer under either of the front seats, similar to this:

Subaru OEM under-seat subwoofer
(click thumbnail to see larger image)

or either of the OEM rear subwoofers made by Kicker, those types of subs will work with an after-market HU without any modifications or special wiring needed.  All of those subs have a T-harness which taps the front speaker outputs and power from the radio's power/speaker harness.  See this post for details (post #4 in my 'Subaru stock HU Info' thread on NASIOC).

On the other hand, if you have a Forester with the odd-shaped under-seat sub shown here, that subwoofer takes a line-level (low level) signal and connects to the factory HU via additional pins on your car's aux harness.  I can build my aux adapter with an additional RCA plug so you can drive your car's sub from your new HU's line-level subwoofer output, similar to this:

Subaru 16-pin aux+sub adapter harness with RCA plugs
(click thumbnail to see larger image)

Price for the aux+sub adapter with 3 RCA plugs as pictured is $39, and includes a remote turn-on wire for the sub.

Additional Signals on Aux Harness

In Foresters with the OEM HU model CP635U1, and 2012-up Impreza (not WRX or STI) and Crosstrek, the factory 16-pin aux harness includes leads for the Parking Brake and Reverse Gear signals.  I can add corresponding wires to my aux harness for an additional $1.50 each.

Retain OEM Microphone

For the Bluetooth phone feature, your car has a factory microphone hidden behind the map light cluster.  The mic is in a small module with an amplifier circuit (see this thread).  The module's audio output is not like an aftermarket HU's mic.  Nobody has documented a good way to interface the OEM mic to an aftermarket HU.  See this thread for one attempt.  Unless you're especially skilled at electronics tinkering, you should plan to use the mic that comes with your new HU.

Dash Kit

The factory HUs in all 2008-up Impreza/WRX/STI, 2009-up Forester, and Crosstreks have a face that is non-standard size (8" wide instead of the standard DIN 7").  You'll need a dash kit to fill the gap or which has a smaller DIN-sized opening.  I don't carry any, but have listed options and more information here.

Parking Brake Bypass

If the HU you're installing is one of the recent Pioneer AVIC X or Z models (e.g., AVIC-X940BT) and you want to do the parking brake bypass mod (so functions aren't locked out while driving and/or so you won't have to connect to your car's parking brake signal), I have a wire with the proper pin that you can easily snap into the vacant slot on the AVIC's RCA harness.  That will save you from needing to extract and transplant the Pioneer's mute pin/wire (which some people find difficult to do).

My bypass wire only fits certain AVIC models, not any others.  Tell me which AVIC model you'll be installing so I can confirm compatibility.  Price is $2.00.

On most Kenwoods, you can simply connect the HU's parking brake lead to chassis ground.

I do not have bypass devices for any other HU models (including Pioneer models starting with AVH–...).  Search on eBay or Amazon.  Be sure that you choose a device that is advertised to work with your specific HU model.  The smaller, solid-state type devices are much better than a huge 30 Amp automotive relay.

Antenna Adapter

Most recent Subaru HUs have a standard Motorola antenna socket on the back, and the car already has an OEM antenna adapter (to convert from Subaru's proprietary antenna plug to Motorola).  I think all non-nav Impreza, Crosstrek, and Forester HUs with built-in BT and USB have the Motorola socket.  Cars with these OEM HU models definitely have the OEM Motorola adapter:

CF225KM, CF425LM, CF435LH, CF525SM, CF605UL, CF625UM, CF735CH, CM221KB, CM421LB, CM621UB, CM631UD, CP235K1, CP335R1, CP425L1, CP435L1, CP625U1, CP635U1, CZ224K1, CZ324R1, CZ624U1

The OEM HUs in a few older Forester models, and cars with Subaru OEM Kenwood navigation have Subaru's proprietary connector.  I have antenna adapters available for $8.  Tell me your OEM HU's model number (usually printed on the front) and I can confirm whether you'll need one.

To Place Your Order

See this page for shipping and payment options.  Let me know if you have any questions.  When you're ready to place your order (or for an itemized quote with shipping), please send the information requested on that page, in the section "To place an order".

Remember to mention you've seen this "Parts Needed" page.