Complete Legacy Wiring Info

[AlpineLegacy06]

Hey guys, this is all the wiring information for 2005+ Subaru Legacy 2.5i/Limited/GT models for those looking to do any electrical mods.

 

If you are installing a remote start system, you would need a bypass (DEI 556UW), this bypass would require you to sacrifice one of your keys in order for remote start to work. I highly recommend having a professional technician work on any electrical component in your car, if precautions are not taken your car could be left incapacitated. If you need any help, I'm an install technician and be glad to answer your questions.

 

Wiring diagram for installing alarms, remote starts, keyless entry, hardwiring radar detectors, etc.:

 

Key:

Ignition harness = bundle of thick gauged wires running from the ignition coil to the BCM

BIU = Body Integrated Unit, black box located to the right of the steering column with 3 plugs coming out of it

(+) or (-) = Indicate the pulse of the wire, + means it's positive with 12volts, - means it's negative with ground

ECM = Electronic Control Module, silver box located behind the glove box

Note: When tapping onto wires, make sure you use a multimeter to check to see if you have the right wire.

12volts (+) white (ignition harness)

 

Starter (+) white/black (ignition harness)

 

Ignition (+) green (ignition harness)

 

2nd Ignition (+) blue (ignition harness)

 

Accessory (+) yellow (ignition harness)

 

Keysense (+) black/white (ignition harness or BIU, 28 pin plug, pin 7)

 

Power Lock (-) brown/white (BIU, 35 pin plug, pin 15)

 

Power Unlock (-) brown/black (BIU, 35 pin plug, pin 29)

 

Lock Motor (5-wire) lt green/yellow (BIU, 35 pin plug, pin 7)

 

Unlock Motor (5-wire) red/green to lt green (BIU, 35 pin plug, pin 23)

 

Parking Lights (+) orange (steering column)

 

Parking Lights (-) black/white (lighting switch)

 

Hazards (-) green to purple/black (turn signal and hazard module)

 

Turn Signal(L) (+) blue/yellow (turn signal and hazard module)

 

Turn Signal ® (+) red/yellow (turn signal and hazard module)

 

Reverse Light (+) brown/yellow (passenger kick panel, rear harness)

 

Door Trigger (-) (BIU, 35 pin plug):LF - blue/white (pin 19)

RF - blue/orange (pin 32)

LR - yellow (pin 31)

RR - white/red (pin 18)

Note: Use All four wires and diode isolate each.

 

Dome Supervision (-) brown (BIU, 30 pin plug, pin 3)

 

Trunk Pin (-) lt green/black (BIU, 35 pin plug, pin 17)

 

Trunk Release (5-wire) white/black (BIU, 35 pin plug, pin 22)

 

Factory Alarm Arm (-) brown (BIU, 35 pin plug, pin 3)

 

Factory Alarm Disarm (-) yellow/red (BIU, 35 pin plug, pin 12)

 

Tachometer (AC) (ECM or gauge cluster):

2.5i/Limited - pink to red/white (35 pin plug, pin 22)

GT - pink to red/white (34 pin plug, pin 23)

Note: Can also be found under the hood at the fuel injector plugs, the wire that is not blue/black, red, or yellow/blue out of 2 wires on each plug.

 

Brake Wire (+) brown/white (brake pedal switch)

 

Parking Brake (-) gray (handle or driver's kick panel, rear harness)

 

Horn Trigger (-) red to red/white (BIU, 30 pin plug, pin 11)

 

Speed Sense (AC) green/black (ABS control module or gauge cluster)

 

Wiring Diagram for installing an aftermarket headunit, 4ch/2ch/mono amplifier, etc.:

 

Note: All wires are located at the radio harness, it's the white plug behind the radio.

 

12volts (+) blue/red

 

Ground (-) black

 

Ignition (+) yellow/red

 

Illumination (+) purple

 

Power Antenna (+) yellow/black

 

LF (+) brown/white

 

LF (-) green

 

RF (+) red/yellow

 

RF (-) white/black

 

LR (+) white/red

 

LR (-) red/black

 

RR (+) blue/yellow

 

RR (-) red/white

[Hanger]

Whoa!!! Nice write up!!! I'm sure this will help alot of people!!

 

This deserves a sticky!!!

[bjmsdrum00]

Whoa!!! Nice write up!!! I'm sure this will help alot of people!!

 

This deserves a sticky!!!

 

+1

[LegacyGT 05]

Cool - thanks! I copied/pasted into a word doc for reference. Hope you don't mind

[AlpineLegacy06]

Cool - thanks! I copied/pasted into a word doc for reference. Hope you don't mind

 

Go ahead, this is 4 u guys.

[jingjing]

cool, thnx

[AlpineLegacy06]

So I guess that would also disable the immobilizer system, eh?

 

It doesn't really disable the immobilizer system. It actually exploits it by having the donkey kong subaru key inside the bypass, thus, the cylinder thinks that the key is in the ignition. The bypass sends a signal from the chip inside the key to a wire ring that wraps around the ignition coil. Basically, the bypass imitates the key so the car thinks the key is starting it up, that's all.

[Fat Charlie]

Greater. The immobilizer isn't disabled, just rendered moot.

 

It's working exactly as designed, checking that there's a properly coded transponder chip nearby. It's just that now there's always a properly coded transponder chip nearby, because you installed one. It's not a security feature any more, even though it's working perfectly well. On the plus side, you can use cheap $5 keys now.

[072]

Properly installed the security system is still intact.

 

It only bypasses the transponder system when the car is remotely started.

 

This means if you tried to jam a screw driver in the ignition switch and got it to turn the car would not start.

 

If you hot wired the car it would not start and the steering wheel lock would still be engaged.

 

If you tryed to use a 5 dollar key the car would still not start.

 

Now this stuff only works if the bypass is installed properly which includes-

-valet key has had teeth ground down or removed -key is securely placed in bypass module and hidden in car to make it difficult to get to

 

At this point, if someone wanted to steal your car, they would have to tear half the dash apart to find a modified key, screwed into a little black box, break that apart, then somehow break the ignition switch, so they can turn it and defeat the steering lock, while holding the key head within a 1/4" of the switch they just tore up.

 

While not impossible, my guess is if someone wanted your car that bad they would just flat bed it away.

 

Tom

[DavidPetrisor]

not true i tryed using a cheap key with my remote start and it would start the car it only works if you start it with the remote start then put in the cheap key so the security feature is still there atleast with the auto page system

[FishingFiend]

This would have saved me so much time earlier this year! Those awesome vacation pics saved me. This is much easier to decipher...

 

+1 for a sticky!

[autoneon]

I am trying to install an ultra start r/s on my '08 2.5i 5 speed

for the clutch, do I just wire directly from the r/s or do I need a relay?

[Swingwing]

OK, so I'm installing a remote start in my 05 2.5i, and I've found everything on the BIU 35-pin plug as described below, except the Arm wire--pin 3 should be Brown, but pin 3 is RED in my car.

The other wires on the plug are as advertised...I tested the lock/unlock and trunk release. Internet search turned up several independent sources that also say pin 3 <<should>> be Brown. The "vacation pix" weren't any help in tracking down the alarm functionality. Any ideas on how to test this wire to see if it's the right one?

 

Factory Alarm Arm (-) brown (BIU, 35 pin plug, pin 3)

Factory Alarm Disarm (-) yellow/red (BIU, 35 pin plug, pin 12)

Power Lock (-) brown/white (BIU, 35 pin plug, pin 15)

Power Unlock (-) brown/black (BIU, 35 pin plug, pin 29)

Trunk Release (5-wire) white/black (BIU, 35 pin plug, pin 22)

[Swingwing]

Here's some feedback from my 562T install. If your remote starter has three heavy gauge 12v input wires, connect all three. On the Valet 562T, the two red input wires power ACC, IG1, and the starter; the red/white wire powers IG2 (HVAC and rear defog).

 

Note:

Tach signal--the ECM is under the carpet below the glovebox. For the 2.5i, I found it much easier place to tap this same wire behind passenger's kick panel: pink wire at pin 19 of 20-pin white connector.

 

Factory Alarm Arm wire--pin 3 was red in my car and didn't arm the alarm. I think we can use the driver's door lock button wire to arm the alarm, but I'll work on that later. For now, I'm using the driver's door lock button to arm the alarm when exiting. The disarm wire does exist and works (yellow/red wire at pin 12 of 35-pin gray plug on BIU).

[chrisinky]

FYI - according to the vacation pics, and my testing, there is no factory alarm arm wire available, its some sort of data/etc interface not a simple pulse.

[chrisinky]

Further info - all, and I mean every wiring guide I found, is incorrect, the Trunk wire is NOT 5wire, its + pulse, thats it. Vacation pics confirm, the trunk is grounded on one side of the motor an the other is + pulse. You still need a relay because most alarms offer trunk output as a - pulse. This is still easier to wire up now because there is not cutting of the factory wire.

 

Also - I would NOT use the net. safety wire to drive a relay - it appears to be EXTREMELY low current from the ECM, It may be safe to use the - when in gear, but don't rely on the + signal when in neutral, ask me how I know!

 

Chris

[Fox06LegacyGT]

i find it hard to believe the trunk on all legacies is not 5- wire. I install remote starts non-stop throughout the winter and have done many legacies including my own.

 

Another worker at my shop accidentally wired the 5 wire relay backwards and blew up the ECM output for the trunk release. The trunk release still works just fine through the aftermarket remote, however the trunk release thru the OEM remote was rendered useless.

 

Regardless, who cares if its only positive? A 5-wire relay is 1 extra wire than a positive switching relay, and there is plenty of room on the legacy to cut the wire to interface with it.

[chrisinky]

So you didn't look at the factory manual, never tested the wire and your calling me out?

 

Look at the diagram from the Subaru factory manual, explain to me the 5 wire part so apparently I am a dumbass.

 

Chris

[coolness]

So can I just install a new HU and use the antenna from my stock HU without disabling the function of the Stock AC system (power). I am guessing yes. I plan to run all new power/speaker wires to the HU in a cubby. Anyone know??

 

I want to install all new speakers (SPS), and Alpine HU so I can add Bluetooth/iPod to my car, but don't want to wreck the AC (I live in AZ), so I don't want to touch the stock wire harness.

 

[Fox06LegacyGT]

So you didn't look at the factory manual, never tested the wire and your calling me out?

 

Look at the diagram from the Subaru factory manual, explain to me the 5 wire part so apparently I am a dumbass.

 

Chris

 

 

Woah, wait a second here. I am in no way calling you a dumbass, just including my own experience in working on these cars.

 

I test every wire before I interface with it and yes, it is a 'positive' trigger in a sense. However, a 5 wire system acts just like a positive trigger, except that the switch side needs to be isolated from the 12v pulse when you activate the trunk release. It very well could be a simple positive circuit.

 

All my information tells me its 5 wire, it acts like a 5-wire system when you test it, and in one case I've known that the BCM side seeing 12v fries the stock remote trunk release. How you choose to wire your car is fine with me. I work on other peoples cars for a living, and I can't afford to possibly mess up their car. So what is the extra hassle of hooking up one extra wire on a relay just to prevent any possible damage from occuring in the first place?

 

Don't get so defensive on a forum. We are all here to help and learn from each other. I am simply trying to voice my input on the subject. In no way was I trying to attack you or what you said.

[chrisinky]

Well, 5-wire is typically to reverse polarity to a motor to move it one way or another, like door locks. With one side of the motor permanently resting at ground there is no reason to treat it as a 5 wire imo.

 

My factory and aftermarket remotes still pop the trunk....

[ILJ]

Need help! pls tell where to tap speed signal in Legacy GT (RHD B13 / BL5).

[mikeislord]

Great post.

[DocHolladay23]

anyone know of a wire that gives 12+ when the headlights are on near the footwell/steering column?

[BAC5.2]

What about the headunit pinouts for the steering wheel controls?