2.0 WRX and STi Standard Harness - Rear Engine Documentation

1 Red w/Blue Stripe

Radiator Fan Power

12v when the ECU requests the radiator fans. Tie this into he power side of your radiator fan and ground the other side of the radiator fan

2 Green w/Red Stripe

Radiator Fan Power

12v when the ECU requests the radiator fans. Tie this into he power side of your radiator fan and ground the other side of the radiator fan

3 Black w/Orange Stripe

Fuel Pump Power from FPC Pin 7

This will go to the power side of your fuel pump

4 Black w/White Stripe

Fuel pump ground to FPC Pin 6

This will go to the ground side of your fuel pump

1 Green w/Yellow Stripe

Vehicle Speed Sensor Input

Requires a digital signal

2 Green

Tachometer

Pulsed output

3 Green w/White Stripe

Oil Pressure

Ground without oil pressure.

4 Red w/White Stripe

Check Engine Light

Sends ground when the check engine light is on

5 White w/Green Stripe

Coolant Temperature

0-5 volt input from the sensor on the engine (resistance-based with pull-up from the cluster)

6 Pink or Black w/White Stripe

Alternator Light Trigger

This goes through a light (or resistor + diode) with a 12V feeding the input side before this wire that is the output.

https://iwireusa.com/blogs/iwire-university/alternator-system-in-your-subaru?_pos=7&_sid=8312438c2&_ss=r

7 Blue w/Yellow Stripe

AC Evap pin 2

12V input tells the ECU that the AC is being requested. Ground output on D27 for the compressor relay

8 Brown

AC Relay

Ground output to the AC compressor relay when A12 gets 12V for the AC request

9 Orange w/White Stripe

12V EXtra output

Tied into ignition or key on power. Can be used to feed the light or other setup for the alternator circuit

Green w/Yellow Stripe

Speed Sensor Signal

To ECU and gauge cluster

Black

Ground

Ground for sensor

Green w/ Red Stripe or Orange w/White Stripe

12v Ignition Power

12v power to sensor

Green w/Black Stripe

Neutral position

Ground output from the transmission to determine in or out of gear

**leave this disconnected if you don’t have the Subaru transmission**

Green w/ Red Stripe or Orange w/White Stripe

12v Ignition Power

12v power to power the reverse light switch

Black

Ground

Ground input into the neutral position switch

**leave this disconnected if you don’t have the Subaru transmission**

Brown w/Yellow Stripe

Reverse Light Output

The output from the reverse light switch will be 12v. Tie this to the reverse lights and ground the other side.

**the output for this wire is also coiled up in the main harness”

1 Red

12v input power

Tie into the ignition circuit coming from the chassis to power up the ECU/Engine fusebox. Make sure this has power while the start is cranking

2 Yellow

Starter Trigger

Tie this into the chassis where the key or switch triggers the starter (small tab on the back, not the battery). This ECU senses when the car is trying to crank so it can adjust and start the engine.