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Old 04-10-2005, 02:32 AM   #2
Scooby Specialist
Member#: 25837
Join Date: Oct 2002
Chapter/Region: South East
Location: Atlanta, GA
1996 SVX L AWD
Laguna Blue Pearl

Default Speaker/power connector

Nearly all Subaru radios from 1995 to 2007 (except SVX), plus some 1993/1994 and some 2008-up use the same, 14-pin connector for speakers, power, illumination, etc.

2008 and up in some Subaru models without Navigation switched to a new 20-pin connector. For details see post #11, below.

Here's a picture of the back of the 2006 WRX radio, courtesy of Bluemanchu (click for larger version):

Main speaker/power connector

Below is a picture of the harness that's wired into the car (also known as the "factory radio harness"). This plugs into the rear of the radio (in the radio picture above, the white socket on the far left side)...

Nearly all* Subarus from 1993 through 2007 (except the SVX) have used this same 14-pin plug for the 4 speaker outputs and power connections.

So any Subaru radio with the 14-pin speaker/power connector will be "plug-and-play" in any other Subaru whose radio had the 14-pin connector (as long as the radio physically fits).

Here's the pin-out for the radio connector, with wire colors in the Impreza/WRX
(the page also has links to wire color variations in the Legacy, Outback, Baja, and Forester).

The above tables apply to the wire colors behind the radio. Be aware that in many years/models, the wire colors change by the time they reach the speakers. Here's a thread that details one example (includes Subaru's wiring diagram): 2001 2.5RS speaker wire color codes

To install your aftermarket head unit, you should use a radio installation harness for Subarus, similar to this (for older years):
or this for newer years:
Don't splice into your factory wires to try to save a few bucks. That frequently causes problems (e.g., blown fuses), and is one of the biggest reasons for the same questions being posted here repeatedly ("Help! I installed a radio and now my car's ___ doesn't work any more!").

*Updated info, courtesy of vrg3:
In North America, 1993 and 1994 Legacies and Justies carried over the pre-1993 connector (actually a two-plug set). SVXs in Europe also use that style of radio harness. Here's a picture from of the corresponding wiring adapter for those models/years:

(click thumbnail for their product page, with more info and larger pictures).

Here's the pin-out for that older style of radio connector. Pin assignments:
View is looking at the contact pins on the car's harnesses (wires pointing away from you).

1990-1994 Loyales used yet a different style of plug:

(click thumbnail for their product page, with more info and larger pictures).
Antenna Control Pin ("antenna remote on")

Earlier Subarus have a rod antenna that you raise or lower by hand. Some have a motorized antenna.

Starting in around 2000, Subarus have the main antenna on the rear glass. Imprezas started in 2004, Foresters as early as 1999. More recently, many models have a stubby antenna on the roof. With all of these, there is an antenna booster amplifier, usually hidden in one of the rear pillars in sedans, or in the tailgate in Foresters and 5-door Imprezas. In this picture of a sedan, it's the box with the "L" sticker. The red arrow points to where the antenna lead connects to the glass foil:

(picture posted by qoncept in this thread "Fix your tinted 04+ radio reception!")

Important note:
On models that have an antenna booster amplifier (or old models with a motorized antenna), when installing an aftermarket radio you must supply +12 volts to the power antenna pin on the radio harness to activate the booster amp or antenna motor. When the antenna amplifier is not 'on', you'll get very poor or no radio reception.

Both the antenna booster amplifier and a motorized antenna require a low-current signal. The booster amp draws about 50mA.

On older cars, the power antenna lead is pin 14 on the 14-pin radio harness. For cars with the 20-pin harness, it's pin 9. On Subarus that use Toyota-style harnesses (10- and 6-pin), it's pin 8 on the 10-pin harness.

(exception: On 2000 and 2001 Foresters, the antenna amplifier is activated directly from Accessory power; the radio harness has no pin/wire on power antenna pin)
All Subaru factory radios since the 1990s provide this signal, whether or not the car it was in had a motorized antenna or antenna booster amplifier.

The radio activates this pin only while you're listening to AM/FM (not disc, tape, or aux) -- so it cannot be used as a remote turn-on for a speaker amplifier.

On an aftermarket radio installation harness (which you should use), the power antenna lead is usually solid BLUE. That is the standard aftermarket color for "power antenna control." The car's factory wire color is usually something different.

When installing an after-market radio, here's what you should connect to the Subaru's antenna control pin (choices from "best" to "worst"):
  1. "Power antenna" output. Most after-market radios have this, usually a solid BLUE wire. This will activate the antenna only while you listen to AM/FM.
  2. Amplifier remote control (usually a BLUE/WHITE wire). Not all after-market radios have this. This will activate the antenna whenever the radio is on, even when you switch to CD or AUX input.
  3. For head units that lack both of the above wires, your only other choice is to connect the Subaru's antenna control pin to Accessory power (+12V switched, aftermarket RED wire). Then the antenna amp will be 'on' (or the motorized antenna will extend) whenever you turn the ignition key to ACC or ON.

Illumination/Dimmer Pins

Subarus have two pins on the radio connector for illumination:
  • Pin 1 ("Illumination +") gets +12 volts when the parking or headlights are on; open-circuit otherwise.
  • Pin 7 ("Dimmer") changes voltage as you adjust the dimmer knob. It varies from about 10 volts (with knob at the dimmest setting) down to 0 volts (with knob at brightest setting). This pin is also called "Illumination - (minus)". Note that this is reverse from many other cars (where 0 volts = dimmest illumination).
The radio illumination lights (and instrument panel lights) are connected between these two lines. So the bulbs effectively "see" a range of 2 volts (dimmest) to 12 volts (brightest).

If you're keeping the factory radio (perhaps adding an amp or sub, or transplanting the radio to another car), you need a harness that has all 14 pins. Most after-market harnesses do not have a wire for the Dimmer pin. Without that pin, the factory radio's illumination will not work at all. See posts starting here.

When installing an after-market head unit that includes a wire for dimmer or illumination: In most cases these HUs only support a two-stage dimming feature -- either full bright (daytime) or slightly dimmed (night driving). Connect this type to pin 1 (the car's illumination(+) signal). You may also need to change a menu option on your HU to enable the dimming feature.

If you have a head unit (or gauge) that wants to see a variable-voltage illumination wire that's not "reversed," (so higher voltage = brighter), you can use this circuit designed by "vrg3" which converts the Subaru's +/- illumination wires into a dimming voltage relative to ground. It's mentioned in this post here on NASIOC (it's worth reading the remainder of the thread too).

Recent Subaru model years (around 2006 and later) 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. This type of dimmer line may or may not be compatible with some HUs or gauges. Check with the aftermarket manufacturer before attempting to use. Also see this post.

Tweeter Connections

The stock radios have only four speaker outputs. The OEM tweeters connect in parallel to wires going to the front door speakers. The tweeter wires branch off either behind the dash or inside the door, depending on the model.

There is a capacitor on the back of each tweeter which serves as a high-pass filter. There is no low-pass filter or crossover for the door speakers.

The wires/plugs are usually present even in cars that did not include the tweeters.

Picture from the 2005 Impreza/WRX wiring diagram:

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Last edited by SVXdc; 03-09-2014 at 03:04 AM.
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