Locate the vehicle’s fuse box cover under the dashboard on the driver’s side. The factory audio wiring harness connects here through a 16-pin plug; pin assignments follow the ISO standard: pins 1–4 carry switched 12V, ground, illumination, and antenna trigger, while pins 5–8 feed speakers–front left positive/negative, then front right positive/negative.
Strip the harness back to reveal color-coded wires–blue (constant 12V), red (switched 12V), black (ground), green/black (front left positive), green (front left negative). Crimp each to the aftermarket head unit’s matching connector using gold-plated terminals; bypass cheap splices with solder and heat-shrink tubing for lasting connections.
Verify polarity with a multimeter before powering up–reverse wiring fries tweeters instantly. Connect the pink/black wire (factory amplifier enable) to the new unit’s remote turn-on lead; failing this silences rear speakers entirely. Test each channel at 75% volume for distortion; adjust crossover slopes via the head unit’s menu if highs crackle.
Store the original schematic behind the glovebox for reference–page 12-4 of the service manual shows the full pinout, including the light blue/yellow wire (steering wheel control data bus). If retrofitting, isolate this wire with electrical tape to prevent voltage feedback into the CAN network.
Vehicle Audio System Connection Guide for the 2001 Sedan
Locate the harness behind the factory stereo unit by removing the center dash panel–typically secured by four clips. The connector will have 16 pins color-coded as follows: wire #1 (black/white) carries constant 12V power from the battery, while wire #4 (red/blue) delivers switched 12V via the ignition. Ground is handled by wire #13 (black) attached directly to chassis metal near the mounting bracket.
For aftermarket speaker integration, match the following factory outputs to standard RCA adapters or ISO harnesses:
| Speaker Location | Factory Wire Color | Connector Pin | Signal Type |
|---|---|---|---|
| Front Left (+) | Light Blue | #5 | Positive |
| Front Left (-) | Pink/Black | #6 | Negative |
| Front Right (+) | Dark Blue/Yellow | #15 | Positive |
| Front Right (-) | Pink/Green | #14 | Negative |
| Rear Left (+) | Yellow/Green | #8 | Positive |
| Rear Left (-) | Black | #7 | Negative |
| Rear Right (+) | Yellow/Black | #9 | Positive |
| Rear Right (-) | Black/Blue | #10 | Negative |
Amplifier trigger wires, if present, are identified as #2 (blue/white) for remote turn-on; this wire must be connected to the aftermarket head unit’s corresponding output to avoid draining the battery. Verify all connections with a multimeter–expected voltage readings should be 12V on power wires and continuity on ground.
If replacing the OEM audio system with a unit lacking a DIN eject button, use a small flathead screwdriver to release the factory fascia–insert the tool into the upper-right slot and pry gently until clips disengage. The harness adapter (Metra 70-8113) simplifies connections but requires splicing the antenna lead (#12, green/white) to maintain FM reception.
For vehicles equipped with premium audio (Infinity), the amplifier harness will include additional wires–orange/black (#3) handles dimmer control while purple (#11) carries speed-sensitive volume input. Bypass these only if the new installation does not support such features; otherwise, terminate them with crimp connectors to prevent short circuits.
Test the setup by inserting the key into the ignition and turning to the ACC position. The new unit should power on without flickering lights or blown fuses–if issues arise, recheck wire #4 (ignition-switched) for proper connection. Secure all loose wires with zip ties and reattach the dash panel before finalizing the installation.
Finding the OEM Stereo Harness Plug in Your Sedan
Start by removing the center console trim panel beneath the climate controls–it snaps off without tools. Locate the retaining clips at each corner; press inward while pulling forward to release. Behind this panel, you’ll find the factory stereo harness connector secured by a plastic clip. The plug is rectangular, about 2.5 inches wide, with 16 discrete terminals arranged in two rows.
Trace the bundle of colored cables exiting the back of the dashboard–these lead directly to the vehicle’s electrical backbone. The harness connector is typically tied to the firewall-side loom with a single cable tie or wrapped in factory tape. Cut or loosen this to free the plug without damaging the wires.
If the connector isn’t immediately visible, check behind the glovebox or kick panel on the driver’s side. Some model variants route the harness along the chassis rail before terminating near the fuse box. The plug’s identifying feature is its unique terminal layout: pins 1-8 on the top row correspond to power, ground, illumination, and antenna, while pins 9-16 handle speaker outputs.
For precise pinouts, reference the vehicle’s service manual–section 8B-2 covers audio system connections. Pin assignments are color-coded: yellow for constant 12V, red for accessory power, black for chassis ground, and solid blue for the powered antenna lead. Speaker wires follow a striped pattern: white/black for front left (+/-), gray/black for front right, green/black for rear left, and violet/black for rear right.
Before disconnecting the harness, label each wire with masking tape or use a multimeter to verify continuity. Set the meter to DC voltage (20V range) and probe the pins with the ignition on–constant power should read 12V at the yellow wire, accessory power at red, and 0V at ground. Speakers will show ~0.5V AC when audio is playing.
If the connector appears melted or corroded, inspect the corresponding terminals in the dashboard harness. Oxidation or bent pins are common failure points–clean contacts with electrical spray and a small wire brush. For replacement, order part number 8629A-10050, which fits multiple years of this platform’s audio systems.
When reinstalling aftermarket components, match the aftermarket harness adapter’s color scheme to the factory wires. Avoid cutting the original harness–splice connections degrade signal integrity over time. Instead, use crimp connectors or solder joints sealed with heat-shrink tubing to maintain waterproofing.
For troubleshooting, probe the harness connector’s empty cavity while the stereo is powered on. A clicking relay or dimming dashboard lights during testing indicates a short–inspect for pinched wires near the transmission tunnel or behind the HVAC controls.
Decoding Wire Colors and Their Roles in the Audio System Schematic
Start by locating the power feed lines–typically a solid yellow cable. This conductor carries a constant 12V supply from the battery, ensuring memory retention for presets and clock settings even when the ignition is off. Verify its function with a multimeter before connecting any peripherals to avoid draining the battery.
The red wire serves as the switched power lead, activated only when the ignition is turned to the “accessory” or “on” position. Interrupting this connection will disable the entire audio unit, so ensure it’s securely fastened to the harness. Confusing this with the yellow lead can lead to unnecessary battery depletion.
Ground connections are almost always black or striped black-and-white. Poor grounding causes hum, distortion, or complete silence. Scrape off any paint or corrosion at the chassis connection point and use a dedicated bolt rather than sharing with other components to prevent interference.
Antenna control is handled by a blue or blue-with-white-stripe wire that triggers automatic power antennas. If your setup includes an aftermarket amp, this lead often doubles as a remote turn-on signal. Keep the run between the head unit and amp under 18 feet to maintain signal integrity.
Speaker outputs follow a consistent color coding: front left positive gray, front left negative gray-black, front right positive white, front right negative white-black, rear left positive green, rear left negative green-black, rear right positive purple, and rear right negative purple-black. Reversing polarity causes out-of-phase audio, resulting in weak bass and hollow-sounding vocals. Always test each pair with a 9V battery before finalizing connections.
Steps to Remove the Dash Panel for Entertainment System Access
Locate the two screws beneath the climate control knobs–use a 7mm socket wrench to remove them. These screws secure the lower trim panel directly below the audio unit. Store them in a magnetized tray to prevent loss.
Grip the upper edge of the center console fascia near the hazard light button. Apply steady outward pressure, starting at the top, then work downward. Plastic clips along the perimeter will release sequentially–you may hear faint pops. If resistance persists, slide a thin plastic pry tool between the panel and the dash to avoid snapping tabs.
- Release the cigarette lighter socket by pulling it straight out–no twisting required.
- Disconnect the dual climate control cables by pressing the small plastic release tabs and gently pulling the connectors free.
- Unclip the hazard button harness by squeezing the sides of the plug while pulling.
Tilt the freed fascia forward to reveal the mounting brackets behind. Two 10mm bolts secure the entertainment module to the chassis–remove these using a ratcheting wrench. Slide the unit forward approximately 3 inches to access the antenna wire and power harness at the rear.
- Detach the main power plug by pressing the locking tab downward with your thumb while pulling the connector.
- For vehicles with premium sound, unplug the amplifier harness hidden behind a small access panel–it’s held by a single Philips screw.
- Remove the ground strap connected to the chassis–it’s secured by a 12mm bolt wrapped in a green wire.
Once the module is fully detached, rest it on the passenger seat without straining wires. Reinstallation follows the reverse process–ensure all connectors snap securely before fastening bolts. Test the climate and hazard functions before reassembling the fascia to confirm proper reconnection.