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#637: 08-07-2009, 04:16 PM
i88 & HU harness wiring instructions
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Location: Atlanta, GA
Car: 1996 SVX L AWD
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OK, for those less experienced at audio installs, here's an annotated picture of how you'll need to connect the various harnesses:
Click image for larger version

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(click to see larger picture)
Your head unit's harness will probably look slightly different every manufacturer uses their own proprietary connector. It may include extra wires that you won't use (you'll need to insulate the ends). Some of the wires (e.g., ground, power antenna control) might have quick-disconnect or fork terminals that you will need to cut off so you can crimp or solder the wire to the 14-pin harness. If it has inline fuse holders, don't cut those off

Installation instructions I've been sending to people:
14-pin Harness
Here's the color code table for the 14-pin harness.

Column "A" shows the colors of the wires at the factory harness plug in the Legacy/Outback. Since you won't be dealing with those wires directly, you can ignore that column. Note that if you have the OEM under-seat sub, you'll be seeing its harness with different colors (and the car's plug is further back in the dash). That is also the case with some aftermarket accessories that your car may have.

Column "B" shows the wires on the "forward" harness. Connect this harness to the one that comes with your new head unit. Although the colors should match, carefully verify the function of each wire with your head unit's installation manual.
Dimmer Lead
For most new head units that have a wire for "Dimmer" or "Illumination," you should connect that to the PLAIN ORANGE wire on the 14-pin harness. This will be in addition to the ORANGE wire on my i88 adapter.

Your HU's dimmer wire could be ORANGE or ORANGE/WHITE. However, your HU may not have an illumination/dimmer wire at all. Some HU's even have an ORANGE or ORANGE/WHITE wire that is not for illumination. Check your HU's installation guide!
FM Antenna Booster Amplifier
Reminder: All Subarus in the last 10+ years have an antenna booster amplifier. You must connect the BLUE wire at pin 14 to something that provides +12V:
  1. Best choice: BLUE "power antenna" or "motor antenna" lead (if your HU has one). That will activate the booster amp (or raise a motorized antenna) only while the HU is in AM/FM mode (off while listening to disc or Aux).
  2. Next best choice: BLUE/WHITE "amp turn-on" lead. That will activate the booster whenever the HU is on.
  3. Last choice (if your HU doesn't have either a BLUE or BLUE/WHITE wire): +12V Accessory (on the 14-pin forward harness, tie the BLUE wire over to the RED wire). This will activate the antenna booster all the time the ignition key is on.
If your aftermarket HU only has the one wire for amp remote turn-on (and no separate wire for power antenna), it is usually OK to connect the HU's amp turn-on lead to both the Subaru's power antenna wire and the remote control input on a speaker amplifier or powered subwoofer. You should check that the total current draw does not exceed the HU's specs (it should say in their wiring instructions). Subaru's booster amplifier draws about 50 mA.

Important: Subaru's antenna booster amplifiers do not work properly with less than 12V (e.g., 11V won't do). So use a voltmeter to verify that your HU supplies at least 12V with everything connected. If you see less than 12V, you'll have to switch to option C.

Some of the Micro Bypass manufacturers also suggest that if you're installing one of those, use option C for the antenna booster. Apparently, the bypass device doesn't play well with the antenna booster.

If you are also installing an accessory device that connects to the AM/FM antenna (such as a traffic data receiver or TV), you may want to use option C so that the device can get reception even when you turn off your HU or switch to a different source (aux, disc, etc.).
i88 Harness Connections
You'll also need to connect the three unterminated wires from my i88 harness to the 14-pin harness as follows:

On harnesses from the latest batches:
  • RED is +12V Accessory. Connect to RED (pin 10).
  • ORANGE is "Illumination +". Connect to ORANGE (pin 1).
  • ORANGE/WHITE is Dimmer or "Illumination " (minus). Connect to ORANGE/WHITE (pin 7).

On harnesses from previous batches:
  • Red is +12V Accessory. Connect to Red (pin 10).
  • Orange is "Illumination +". Connect to Orange (pin 1).
  • Orange marked with a piece of white heat shrink tubing is Dimmer or "Illumination " (minus). Connect to Orange/White (pin 7).

On harnesses from older batches:
  • Red is +12V Accessory. Connect to Red (pin 10).
  • Orange is "Illumination +". Connect to Orange (pin 1).
  • Yellow/Orange is Dimmer or "Illumination " (minus). Connect to Orange/White (pin 7).

On harnesses from the earliest batches:
  • Red is +12V Accessory. Connect to Red (pin 10).
  • Yellow/Orange is "Illumination +". Connect to Orange (pin 1).
  • Yellow/Black is Dimmer or "Illumination -". Connect to Orange/White (pin 7).
Joining Wires
When you solder wires (which I recommend, since it can give the smallest and most secure connections), it's best to twist them together in a double-spiral, like the wires at the top of this picture:
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I found this Basic Soldering Howto with more pictures and instruction on Also search YouTube for videos.

When joining three wires, twist the first two, pointing towards each other like above, then spiral the third wire around the first junction, and finally solder everything together.

Remember to slide on your heat shrink tubing before you twist the wires together!

Here's the harness I wired up for my SVX:
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For people who don't want to solder, crimp caps are a good method (better than butt splice crimps, since the wires will be twisted together -- making direct contact to each other -- before you crimp). Posi-Locks are a good, tool-free (and reusable) alternative. Crutchfield sells both.

Last edited by SVXdc; 02-27-2017 at 12:11 PM.. Reason: 6/6/2015 Revamp, & added notes about FM booster amp requires >= 12V; 2/27/2017 replaced wiring pic [p# 2312]
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