Parts Needed
to install an after-market Head Unit

Applicable to:
2012–up Subaru Impreza & Crosstrek *
(not WRX, STi, or Forester)

* Car models whose OEM Head Units do not have OEM Subaru Navigation
but do have built-in USB and Bluetooth

For other Subaru models and trim levels, see the main 'Aftermarket HU Parts Needed' page

When you contact me, let me know you've seen this "Parts Needed" page.

Power/Speaker Wiring Harness

All of the above models whose OEM head units (radios) have built-in USB and Bluetooth (i.e., steering wheel includes Off-hook, On-hook, and Talk buttons) use Subaru's 20-pin harness for the power and speaker connections to the HU.  You will need my 20-pin "forward" harness with 3 SWC wires ($12,  link).

You'll need to solder or crimp my harness to your new HU's power/speaker harness, creating an adapter that is mostly "plug-and-play."  See my Subaru 20-pin HU installation guide.

Vehicle Speed Signal

On these models,  the  factory 20-pin power/speaker harness includes a wire which provides the Vehicle Speed Signal (VSS) on pin #19.  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).

Incidentally, Subaru models with VSS on the 20-pin radio harness no longer have CAN bus there.

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, etc.  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 this page: .

To install, you will need to solder (recommended) or crimp some of the interface module's wires to my 20-pin harness and your new HU's harness.  I can't pre-wire the harnesses for you, since you will need to combine with your new HU's harness.

Retain Factory Aux Jack

Your factory HU has a 16-pin socket on the rear for its stereo aux input.  A factory harness connects from the back of the HU to the back of the 3.5mm aux jack in your armrest center console.  That harness has proprietary plugs at both ends.  The harness only handles the aux socket — not USB.  See more information about USB below.

I make an aux adapter harness you can use to retain your factory aux jack with an aftermarket HU.  See this page: Subaru 16-pin aux harness.  The white 16-pin connector on my aux adapter fits the end of the factory aux harness that is (or was) plugged into the back of your factory-installed HU.  My aux harness retains the stereo aux jack only, not the USB socket.

Also see next section for additional signals your car has on the 16-pin aux harness that you may want.

Additional Signals on Aux Harness

On all 2012–up non-navigation Crosstrek and Impreza models (not WRX or STi), the car's factory 16-pin aux harness includes leads for the Parking Brake (pin #15) and Reverse Gear signal (pin #16).  I can build my aux harness with corresponding wires.  See the 16-pin aux harness page for details.

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.

I have a plug-and-play Subaru USB adapter cable you can use to retain your factory USB socket with an aftermarket HU.  See this page: Subaru USB adapter.  Price is $12.

Subaru USB Retention Adapter
(click thumbnail to see larger image)

The Hirose-style socket on my USB adapter fits the end of the factory USB harness that is (or was) plugged into the back of your factory-installed HU.  Opposite end is a standard male USB "A" plug (which you'll plug into your new HU's rear USB input).  Length of the cable is ~6" (147 mm) between the two connectors.  That differs from Metra's AX-SUBUSB (which is ~19" or 480 mm).  Using shorter cables helps to supply more 5V current to your USB device.

Before Ordering Aux and/or USB Adapters

Study the connection diagrams in your new HU's installation manuals.  With the cables and interface adapters required for some phones or iPods, it's sometimes not practical to retain your car's factory aux or USB sockets (due to the physical layout of all the pieces).

Older iPods sometimes use an 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.

Also note: Pioneer AppRadio models SPH-DA01, SPH-DA02, SPH-DA100, and SPH-DA210 do not have any aux inputs!  The new AppRadio 4 (SPH-DA120) does have an aux input (finally!).  I'm not referring to other recent Pioneer models with AppRadio mode.

If you're in doubt, check your HU's installation manual to see whether yours has any rear aux inputs.

Retain OEM Subwoofer

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

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

...or one of the OEM accessory 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 power, ground, and the front speaker outputs from the radio's power/speaker harness.  See this post for details (post #4 in my 'Subaru stock HU Info' thread on NASIOC).

Can't 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 analog electronic circuit design, you should plan to use the mic that comes with your new HU.

Retain OEM Camera

If your car has a factory-fitted rear view camera that is displayed on your OEM HU, I can probably provide a harness to retain the camera with an aftermarket HU.

Note: Subaru HUs supply 6 Volt power to the OEM cameras.  The cameras operate internally at 3.3V and have a built-in voltage converter.  In most models, you should give the camera something close to 6V, to prevent the camera's converter from overheating.  However, the voltage converter in the Crosstrek's camera has been confirmed to work with an input up to 40V without any problem.

E-mail me to discuss what kind of "OEM rear camera retention" harness you'll need.

Note that the 8- and 16-pin camera harnesses currently listed in my 'Products' pages are to connect an aftermarket camera into certain OEM HUs.

If your car has an OEM camera being displayed in the mirror, I don't have any plans to offer a harness to re-direct that to an aftermarket HU.

Multi-Function Display (MFD)

2012–up Impreza and Crosstrek models have a Multi-Function Display (MFD) at the top of the dash, above the head unit and A/C vents.  When you switch to an aftermarket HU, the MFD will continue working as before.

Some models have an OEM camera shown on the MFD.  I've made harnesses for a few people to re-direct the OEM camera to an aftermarket HU.  I've also made harnesses to connect an aftermarket camera to an MFD in cars which don't have a factory camera.  I can also make a harness to re-direct an OEM camera from the MFD to an OEM HU with rear camera capability.  However, I have suspended offering all of these MFD camera harnesses, pending some additional research on the MFD.  If you would like to be notified when these are available again, let me know.

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.

2012–up Impreza & Crosstrek models have a new dash design which requires different dash kits than the previous 2008–up Impreza and Forester models.

I don't carry any dash kits, but have listed options and more information here.

AVIC Parking Brake Bypass

See this page: Pioneer AVIC parking brake bypass wire.

My AVIC bypass wire does not fit any of the new AVIC NEX models, nor any of the old models (AVICD3, Z2, FxxxBT, UxxxBT, etc.).  For all of these other AVIC models, see the forums at  A software-only hack was found for the NEX navigation models (and it's been confirmed that you don't even need to connect the HU's parking brake lead).

On most Kenwoods, some recent JVCs, Parrot Asteroid Smart, most Chinese HUs, and perhaps all HUs designated for markets outside North America, you can simply connect the HU's parking brake lead to chassis ground.

I do not have parking brake bypass devices for any other aftermarket 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 a male Motorola antenna plug).  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 and do not need an aftermarket antenna adapter:

CM221KB, CM421LB, CM601U1, CM621UB, CM631UD

If your Subaru's OEM HU is not one of the above models, you may be on the wrong 'parts needed' page for your car.  Otherwise, please tell me your OEM HU's model number (printed on the front) so I can verify whether you'll need an antenna adapter.

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.

© Copyright 2014 by David Carter.  All rights reserved.