Complete 2015 Subaru Impreza Radio Wiring Diagram and Installation Guide
Locate the color-coded harness behind the dashboard fascia–typically bundled with the climate control module. The primary connectors include yellow (constant 12V), red (switched 12V), black (ground), blue/white (antenna trigger), and orange (illumination). Verify pin assignments using a multimeter before disconnecting factory plugs to avoid airbag or ECU disruptions. Factory amplifiers in sedan variants often require speaker-level inputs; resistance must match aftermarket units (4-8 ohms) to prevent distortion.
For base trims, bypass resistors are unnecessary, but premium models with Harman Kardon systems demand high-to-low impedance adapters. The data bus connection (green/white wire) controls volume and chimes–severance disables steering wheel controls. Use a wiring interface (Metra ASWC-1 or similar) to retain functionality; solder and heat-shrink all splices to prevent corrosion.
If retrofitting a double-DIN unit, check dashboard depth clearance–OEM bezels require trimming for some Pioneer or Kenwood models. For navigation-enabled setups, confirm GPS antenna compatibility (most aftermarket units need an external module). Reset the vehicle’s infotainment system by disconnecting the negative terminal for 10 minutes if error codes persist post-installation.
Fuse ratings: 10A for accessory circuits, 15A for power leads. Replace blown fuses with identical ratings–avoid copper substitutes. Ground connections should be attached to bare metal (sand paint if necessary) near the original mount point to eliminate noise. Test all functions (AM/FM, Bluetooth, USB) before reassembling panels to ensure signal integrity.
Connecting the Audio System in Your Sedán: A Pinout Breakdown
Begin by locating harness connector B230 behind the factory head unit–it’s the 12-pin rectangular plug with labeled cavities. Pins 1 (red/green) and 2 (yellow) supply constant 12V and ignition-switched power respectively; confirm voltage with a multimeter before splicing to aftermarket adapters. Ground sits on pin 12 (black), critical for noise-free transmission; verify surface conductivity on the chassis bolt shared with the HVAC bracket.
Speaker outputs occupy the remaining terminals:
- Front left (+) – pin 7 (violet)
- Front left (–) – pin 8 (violet/black)
- Front right (+) – pin 5 (gray)
- Front right (–) – pin 6 (gray/black)
- Rear left (+) – pin 9 (white)
- Rear left (–) – pin 10 (white/black)
- Rear right (+) – pin 3 (green)
- Rear right (–) – pin 4 (green/black)
Antenna trigger appears on pin 11 (blue), requiring 12V on activation for motorized mast extension. Isolate each circuit with a 10A fuse inline whenever modifying connections; factory schematics show tapped wires routed through T-harness above the glove box–trace these paths to avoid accidental shorts during upgrades.
Matching the Right Cable Assembly for Your Premium Audio System
Begin by locating the OEM connector behind the factory head unit–it’s a 16-pin Metra AX-BEL or similar interface specific to the model year’s harness layout. Verify the pinout configuration against part number 70-8113, which accommodates both power leads (constant, switched, ground) and speaker outputs (front/rear, left/right) without modification. Counterfeit adapters often omit the antenna trigger wire or misalign the illumination circuit, leading to intermittent backlight failures.
Use a multimeter to confirm continuity on each lead before installation. The schematic below outlines critical connections:
- Red (switched 12V) – fuse #15 (10A) on the instrument panel junction
- Yellow (constant 12V) – fuse #30 (15A) under the dashboard
- Black (ground) – chassis bolt behind the climate controls
- Orange/white (illumination) – dimmer circuit tied to the headlight switch
- Blue/white (power antenna) – activates motorized mast
Skip universal harnesses unless they include a dedicated subwoofer output for premium trims.
For aftermarket upgrades, prioritize harnesses with built-in amplifier bypasses if retaining the stock amplifier (part #86241AG00A). Models equipped with navigation require an additional data bus converter (e.g., PAC RP4-SU11) to retain steering wheel controls and vehicle settings integration. Avoid splicing the CAN bus wires–damage risks disabling climate control or dash displays.
Secure connections with adhesive-lined heat shrink tubing; standard electrical tape degrades under dashboard heat cycling. Inspect the harness for labels–legitimate units include a QR code linking to the manufacturer’s pinout PDF. If installing a double-DIN unit, confirm compatibility with the vehicle’s climate control housing depth to prevent air vent obstruction.
Step-by-Step Guide to OEM Audio System Pinout and Circuit Identification
Begin by locating the harness connector on the back of the stock head unit–it’s a 14-pin rectangular plug with a distinct latch mechanism. Use a small flathead screwdriver to release the clip and carefully disconnect the assembly. Label each wire as you proceed, marking them with adhesive tape and a permanent marker to match the following color codes and function assignments.
| Wire Color | Purpose | Voltage (Idle) | Connection Notes |
|---|---|---|---|
| Yellow with red stripe | Battery (+12V constant) | 12.3–13.8V | Connect to aftermarket harness red wire; fuse required (10A) |
| Black with yellow stripe | Ignition (+12V switched) | 0V (off), 12.3–13.8V (on) | Link to new unit’s ignition wire (orange or yellow) |
| Solid blue | Amplifier remote turn-on | 12V when audio system active | Splice to aftermarket blue/white lead for powered speakers |
| Green with black stripe | Left front speaker (+) | 0.5–4V AC (audio signal) | Pair with solid green for (-); check polarity at door tweeter |
| Solid green | Left front speaker (-) | N/A | Twist with green/black for balanced signal |
| Red with black stripe | Right front speaker (+) | 0.5–4V AC (audio signal) | Combine with solid red for ground reference |
| Solid red | Right front speaker (-) | N/A | Confirm phase at factory tweeter connector |
| White with black stripe | Left rear speaker (+) | 0.5–4V AC (audio signal) | Match with solid white; verify at trunk harness |
| Solid white | Left rear speaker (-) | N/A | Use multimeter continuity test for correct pairing |
| Gray with black stripe | Right rear speaker (+) | 0.5–4V AC (audio signal) | Attach to solid gray; check trunk sub-connector |
| Solid gray | Right rear speaker (-) | N/A | Avoid shorting to chassis ground |
For ground connections, identify the bare black wire or black with yellow stripe–these terminate directly to the vehicle’s chassis. Scrape off any paint or corrosion at the grounding point (typically a bolt near the unit’s mounting bracket) and secure with a star washer for optimal conductivity. Always test continuity between the ground wire and chassis before finalizing connections.
When integrating an aftermarket stereo, use a pinout adapter or splice each lead individually. For stealth installs, retain the factory antenna motor wire (solid brown) and park it–it carries no signal but prevents dashboard error codes. If adding a backup camera, repurpose the violet wire (reverse signal) and connect it to the new unit’s camera input, ensuring the camera’s power draw doesn’t exceed 300mA to avoid triggering OEM circuit protection.
Finding the Fuse Panel and Audio System Electrical Connections in Your Vehicle
Begin by opening the driver-side door and locating the small panel beneath the dashboard. This cover is typically positioned to the left of the steering column, near the hood release lever. Remove the clip or screw securing it in place to reveal the primary fuse box.
Identify the fuse labeled “AUDIO” or “ACC” (accessory) inside the panel–these supply power to the entertainment unit. Use a multimeter to verify 12V at the fuse terminals when the ignition is turned to the accessory position. If voltage is absent, check neighboring fuses marked “IGN” or “CIGAR” as alternative power sources.
The secondary power distribution point is behind the glove box. Remove the three screws holding the glove compartment in place and pull it downward gently to access the wiring harness. Look for a 10-pin connector with pink and yellow wires–these feed constant and switched power to the head unit.
Trace the pink wire to its origin at the fusible link near the battery. This line provides uninterrupted power for memory functions like presets. The yellow wire links to the ignition switch and supplies voltage only when the key is in the “on” or “accessory” position.
Verifying Connections Under the Dashboard
Peel back the lower dashboard trim panel on the driver’s side to expose the back of the audio system’s mounting bracket. Locate the large rectangular connector plugged into the rear of the unit. Inspect the pins for corrosion or bent terminals–these often cause intermittent power loss.
Ground connections are critical. Follow the black wire from the harness to its grounding point on the chassis. This is usually a bolt near the kick panel or under the carpet. Clean the contact surface with sandpaper if oxidation is present, then reattach securely.
If the system remains non-operational, check the inline fuse in the power harness behind the unit. This 15-amp fuse protects the amplifier circuit. Replace it if blown, but first address any short circuits in the speaker wires or harness that may have caused the failure.
For models with steering wheel controls, locate the control module behind the upper dashboard trim near the driver’s knee. The module’s connector shares power with the head unit–ensure it is firmly seated and free of moisture.