Complete 2014 Subaru Forester Radio Wiring Color Code Guide
Start by locating the OEM harness behind the factory head unit. On the left-side connector (typically a 20-pin plug), pins 12 (yellow) and 14 (red) deliver constant and switched 12V power respectively, while pin 16 (black) provides the ground. The right-side connector (usually a 12-pin plug) carries speaker wires: front left (+)/(-) on pins 2/1, front right (+)/(-) on pins 6/5, rear left (+)/(-) on pins 10/9, and rear right (+)/(-) on pins 12/11. Verify each wire with a multimeter before disconnecting–resistance should read below 4 ohms for functional speakers.
For aftermarket units without a dedicated wiring harness adapter, strip and crimp the corresponding wires using AWG 16-18 gauge copper wire with solder-seal connectors. Avoid twisting bare wires, as oxidation can degrade signal quality within months. If retaining steering wheel controls, identify the data bus wire (often pin 4 on the left connector, typically grey with a blue stripe) and connect it to an ASWC-1 or Metra Axxess interface module. These modules require 5V reference voltage from the vehicle’s system–test for it on pin 1 (pink) of the OEM harness.
Subwoofer integration demands filtering low frequencies. Tap into rear speaker wires (left and right) and route them through a line-level converter if the amplifier lacks high-level inputs. Set the converter’s gain to match the factory system’s 2.5V RMS output. Ground the amplifier’s power wire directly to the chassis near the factory ground point (usually behind the rear seat or cargo area), using M8 or M10 bolts–never share grounds with other accessories. For vehicles with Starlink telematics, disconnect the battery before splicing any wires to prevent triggering error codes.
LCD screens in newer replacement units often require a RGB video feed. Locate the composite video wire (typically pin 8 on the right connector, pink or purple) and connect it to the aftermarket unit’s video input. If the factory rearview camera is retained, ensure compatibility with the new head unit’s CVBS signal standards–some aftermarket systems require a resistor-based voltage divider to adjust the 1V p-p signal to the required 0.7V p-p. Always re-secure all harnesses with zip ties away from sharp edges or moving parts to prevent chafing.
For vehicles with premium audio systems (e.g., Harman Kardon), additional steps are necessary. The amplifier’s signal-sense wire (usually pin 3 on the left connector, grey) must remain connected–disconnecting it will disable the entire system. If upgrading to a source unit with built-in amplification, bypass the factory amp by tapping into the pre-amp outputs from the head unit, not the speaker wires. Use RCAs with gold-plated connectors and shielded cables to minimize interference, particularly in models with proximity sensors or lane-keep assist.
Connecting Aftermarket Audio Systems in Your Crossover Vehicle
Locate the factory harness behind the dashboard cluster–typically a 12-pin ISO connector with color-coded leads. Pinout details: red (constant 12V), yellow (switched 12V), black (ground), blue/white (antenna trigger), and orange/white (illumination). Mismatched voltages between stock and aftermarket units are a common pitfall; verify with a multimeter before splicing. For vehicles equipped with premium audio, retain the amplifier interface by identifying the six-channel output wires (speakers) or fiber-optic connections if applicable.
Troubleshooting Common Installation Errors
Ground loops produce a low-frequency hum–secure all grounds to bare metal at a single point near the unit’s mounting location. If audio cuts out when the engine starts, install a noise filter on the power line or reroute the harness away from ignition coils. Aftermarket adapters like Metra ASWC-1 simplify steering wheel control integration; bypass the OEM amplifier only if the new head unit’s power ratings (45W x 4 channels min) match or exceed factory specs. Check for blown fuses if the display dims–swap the red and yellow leads if powered accessories lose memory settings.
Speaker polarity matters: positive wires (gray, green, purple, white) striped, negatives solid. Use a 9V battery to test each door speaker–brief contact should produce a sharp pop; reverse polarity if the sound is weak. For subwoofer upgrades, tap into the rear channel outputs (green/violet) or install a line-out converter if the head unit lacks dedicated RCA jacks. Avoid daisy-chaining power wires–run a dedicated 12-gauge cable directly from the battery with an in-line fuse (15A–20A) within 18 inches of the terminal.
Climate control interference affects some models–relocate the GPS antenna lead (pink) away from the HVAC ducts. For vehicles with satellite tuners, retain the telematics module by preserving the brown vehicle speed signal wire. If Bluetooth pairing fails, reset the head unit to factory defaults and ensure the microphone wire (pink, 4-pin) is connected to the correct pin on the aftermarket harness. Prior to finalizing installation, test all functions (USB, aux, FM reception) while the engine runs to identify interference sources early.
Finding the OEM Head Unit Connector Pin Configuration
Remove the trim panel beneath the climate controls first–it snaps off with minimal force. Behind it, the factory harness attaches via a 20-pin rectangular plug (A) and an 8-pin square plug (B). Pin layouts for both are as follows:
- Connector A:
- Constant +12V power (yellow/red striped)
- Switched ignition +12V (red/black striped)
- Ground (black)
- Front left speaker (+) (brown)
- Front left speaker (-) (brown/black striped)
- Front right speaker (+) (light green)
- Front right speaker (-) (light green/black striped)
- Rear left speaker (+) (white)
- Rear left speaker (-) (white/black striped)
- Rear right speaker (+) (green)
- Rear right speaker (-) (green/black striped)
- Antanna trigger (pink)
- Mute signal (grey/red striped)
- CAN High (yellow/blue striped)
- CAN Low (yellow/green striped)
- Illumination (red/white striped)
- Ground for accessory circuits (black/white striped)
- Reverse signal (green/white striped)
- Parking brake signal (blue/white striped)
- Speed pulse (blue/red striped)
- Connector B:
- USB power (red)
- USB data (-) (white)
- USB data (+) (green)
- Ground (black/red striped)
- iPod detect (purple)
- Aux L (grey)
- Aux R (brown)
- Aux ground (black/yellow striped)
Use a multimeter set to continuity mode to verify each pin before connecting aftermarket equipment. Probe the harness side of the connector, not the pins themselves, to avoid bending them. Misaligned connections risk damaging both the new unit and the vehicle’s electrical system.
Identifying Hidden Wiring
Some models include an additional 6-pin connector (C) behind the glove box. This feeds the satellite tuner, if equipped. Pins are:
- 1: +12V constant
- 2: CAN High
- 3: CAN Low
- 4: Ground
- 5: Data
- 6: Clock
Label every wire before cutting or splicing. Even a single misrouted cable can trigger dashboard warning lights or disable safety features like rear-view camera input.
Matching Aftermarket Receiver Harness Wires to Vehicle Circuit Colors
Locate the constant 12V power wire–typically solid yellow or yellow with a thin stripe–near the factory connector’s pinout by testing with a multimeter set to 20V DC. This line maintains memory settings and must connect directly to the corresponding aftermarket harness lead without intermediary splices to prevent voltage drop. Verify continuity with the battery’s positive terminal while the ignition is off; any fluctuation indicates a faulty fuse or degraded wiring requiring inspection.
Identify the switched power feed, often red or red with a stripe, which activates only when the key is in the ACC or ON position. Cross-reference this with the vehicle’s fuse box diagram to confirm the correct fuse rating–usually 10A–to avoid overloading the circuit. Connect this wire to the aftermarket unit’s ignition input, ensuring no parasitic drain occurs when the system is off; a relay may be necessary if the draw exceeds 0.5A.
Ground connections demand attention to location and conductivity. The factory ground wire–black or black with a stripe–attaches to a chassis point with minimal resistance, typically near the original receiver’s mounting bracket. Scrape away paint or corrosion until bare metal is exposed, then secure the ring terminal with a stainless-steel screw torqued to 10-12 lb-in. Test resistance between the ground wire and the battery’s negative terminal; values above 0.5 ohms signal a poor connection needing rework.
Speaker outputs use a dual-color coding system: solid hues for positive leads and striped variants for negatives. Front left outputs often appear as solid gray and gray/black, while rear right channels may use solid violet and violet/black. Validate polarity with a 9V battery test–briefly touch the speaker wires to the battery terminals; a distinct pop confirms correct orientation. Reversing polarity weakens bass response and distorts midrange frequencies.
Amplifier trigger wires–blue or blue/white–activate external amplifiers when the aftermarket unit powers on. Verify compatibility with the amp’s remote turn-on input, as some OEM amplifiers require a higher pull-in voltage (12V) than standard head units provide (4-6V). A relay can bridge this gap, but ensure the wire gauge supports the amp’s current draw–18AWG suffices for most setups, though 16AWG is safer for high-power systems.
Illumination wires–orange or orange/white–dim the display in sync with the dash lights. Connect these to the factory dimmer circuit; failure to do so results in either constant brightness or complete darkness. Test by toggling the headlight switch; the aftermarket unit’s brightness should adjust proportionally. If dimming is inverted, swap the positive and negative leads at the harness connector.