Pin |
Function |
Notes |
After - Market Harness Wire Colors (EIA Standard) |
Subaru Factory Radio Harness OEM Wire colors |
|
2008–2011 Impreza |
2009–2011 Forester |
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1 | Illumination + |
+12 volts when you use the headlights switch to turn on the parking lights or headlights. This pin is open-circuit when the lights are off. For nearly all aftermarket HUs that have a wire for dimmer or illumination control, you should connect that wire to the Subaru's pin 1. |
Orange / White | Violet | Violet |
2 | Dimmer (Illumination –) |
Varies as you adjust the car's dimmer knob. On Subaru models up to around 2006, this line varies in voltage from close to 12 volts (with the knob at the dimmest setting) down to 0 volts (with dimmer knob at brightest setting). Note that this is backwards from the method used in some other cars. The car's instrument panel lights are connected between the illumination and dimmer lines. So the bulbs effectively see a range of voltage from 0 volts (dimmest) to 12 volts (brightest). Recent model years have changed to LEDs for the instrument panel lights. In these cars, the dimmer wire provides a pulse-width modulated signal (12V switched rapidly on and off). The dimmer knob adjusts the percentage of on time, causing the LEDs to appear dimmer or brighter. |
Orange / Black | Black / White | Black / White |
3 | +12 Volt Accessory (switched) | Gets +12V when you turn your ignition key to Accessory or On. This wire is what causes the radio to turn off when you turn off the key. Some HUs label this wire Ignition. | Red | Yellow / Red | Yellow / Red |
4 | Steering Wheel Controls (SWC1+) |
Wires connected to the car's Steering Wheel Audio Controls (SWCs). In Subarus, all SWC wires go directly between the HU and the wheel. Neither side connects to ground or a voltage in the car. Inside the wheel, the buttons connect to a network of resistors. The HU sees a different resistance for each button (and a higher value when no button is pressed). Many HUs today can work with OEM SWCs. However, most HUs require a separate interface module (to convert from the Subaru's resistors to what the HU expects to see). On most models/years: Pin 4 connects to the buttons for Mute, Volume Up/Down, Mode, and Channel/Seek Up/Down. |
Brown / Red | Brown | Lt Green / Red |
5 | Left Rear Speaker – | Green / Black | Red / Black | Red / Yellow | |
6 | Left Rear Speaker + | Green | White / Red | White / Black | |
7 | Left Front Speaker – | White / Black | White / Black | Brown / White | |
8 | Left Front Speaker + | White | Blue / Orange | Brown | |
9 | Antenna Booster Amplifier Power + |
Powers an antenna booster amplifier (for the foil antenna on the rear glass or short antenna on the roof). Subaru OEM radios send +12V to this line only while you're in AM/FM mode. This line won't work to control an aftermarket speaker amplifier — the amp would only work while you listen to radio (not disc, aux, satellite, etc.) When installing an aftermarket HU, make sure this wire gets no less than 12 Volts. |
Blue / White | Yellow / Black | Yellow / Black |
10 | Ground | Black | Black / Blue | Black | |
11 |
Impreza / Forester: CAN Low (data bus) Legacy / Outback: Steering Wheel Controls (SWC2+) |
CAN (Controller Area Network) is a data bus that allows various devices in the car to communicate with each other. 2010–2012 Legacy/Outback with phone/BT SWC buttons: On/Off-Hook and Talk buttons. These buttons share the same common wire (pin 14). 2010–2012 Legacy/Outback with phone/BT SWC buttons: On/Off-Hook and Talk buttons. These buttons share the same common wire (pin 14). |
Brown / Yellow | Lt Green / Red | Blue |
12 |
Impreza / Forester: CAN High (data bus) Legacy / Outback: Body Integrated Unit |
Brown / Green | Pink | Pink | |
13 | Impreza / Forester w/ BT: Steering Wheel Controls (SWC2+) 2012–2013 Legacy / Outback with OEM HU CE617U1: SWC2+ 2010–2012 Legacy / Outback: +12V Ignition (ON/RUN) |
Impreza/Forester with phone/Bluetooth SWC buttons: Mode and On/Off-Hook and Talk buttons. These buttons share the same common wire (pin 14). | Brown / Blue | Blue / White | [Red] |
14 | Steering Wheel Controls – (common) | Brown / Black | Yellow | Yellow | |
15 | Right Rear Speaker – | Violet / Black | Red / White | Gray / Red | |
16 | Right Rear Speaker + | Violet | Gray / Green | Gray | |
17 | Right Front Speaker – | Gray / Black | Green | Blue / Yellow | |
18 | Right Front Speaker + | Gray | Brown / Yellow | Blue / White | |
19 | Some models (see footnote): VSS Legacy / Outback: +12V Battery (different circuit) |
Vehicle Speed Signal (VSS) present in these models: 2012–up Impreza (not WRX or STi) and Crosstrek 2014–up Forester 2015–up WRX & STi |
— | — | — |
20 | +12 Volt Battery (Memory) (R) | Pin 20 connects to the car's battery (through a fuse in the panel under the hood) and gets +12V all the time. Pin 20 has a larger-gauge wire. | Yellow | Blue / Red | Blue / Red |