Kenwood KDC 138 Wiring Diagram Manual

The Kenwood KDC 138 is a single DIN car stereo receiver with CD player, AM/FM radio, USB input, auxiliary input, and Bluetooth connectivity. This manual provides detailed wiring diagrams and installation instructions for proper connection to vehicle electrical systems, speakers, and external devices. Below are key sections for wiring specifications, connection diagrams, installation procedures, and troubleshooting.

1. Wiring Specifications 2. Connection Diagrams 3. Installation Procedures 4. Wire Color Codes 5. Speaker Connections 6. Power Connections 7. External Device Connections 8. Antenna Connections 9. Safety Precautions 10. Troubleshooting Wiring Issues

Wiring Specifications

Key wiring components: Main wiring harness, antenna connector, USB extension cable, remote control input, external device connections.

Wire Type	Specification
Power Supply	12V DC negative ground
Current Consumption	Max 10A
Speaker Output	50W x 4 channels max
Speaker Impedance	4-8 ohms
USB Input	5V DC, 500mA max
Auxiliary Input	3.5mm stereo mini jack

Connection Diagrams

Main wiring harness connections and pin assignments.

Power Connections: Yellow (B+), Red (ACC), Black (GND)
Speaker Outputs: White/White-black (Front L), Gray/Gray-black (Front R), Green/Green-black (Rear L), Purple/Purple-black (Rear R)
Control Wires: Blue/White (Amp Remote), Orange (Illumination), Pink (Mute)
Audio Inputs: Brown (Phone Mute), External device connectors

WARNING! Always disconnect vehicle battery before beginning installation to prevent electrical shorts.

Installation Procedures

Step-by-step wiring installation guide.

Disconnect negative battery terminal for safety
Remove factory radio following vehicle-specific instructions
Connect main wiring harness using proper adapters
Connect speaker wires following color coding
Connect power wires (Yellow to constant 12V, Red to ignition switch)
Connect ground wire to clean metal chassis point
Test all connections before final assembly

CAUTION! Ensure all connections are secure and insulated to prevent shorts.

Wire Color Codes

Yellow: Battery +12V (Constant)
Red: Accessory +12V (Switched)
Black: Ground
Blue/White: Power Antenna/Amplifier Remote
Orange: Illumination/Dimmer
White: Front Left Speaker (+)
White/Black: Front Left Speaker (-)
Gray: Front Right Speaker (+)
Gray/Black: Front Right Speaker (-)
Green: Rear Left Speaker (+)
Green/Black: Rear Left Speaker (-)
Purple: Rear Right Speaker (+)
Purple/Black: Rear Right Speaker (-)

Speaker Connections

Proper speaker wiring for optimal sound quality and protection.

Front Speakers: White/White-black pairs to front left and right channels. Rear Speakers: Green/Green-black and Purple/Purple-black pairs to rear channels.

Speaker Polarity: Maintain proper +/- connections for correct phase. Speaker Impedance: Use 4-8 ohm speakers only. Power Handling: Match speaker power handling to receiver output.

Power Connections

Critical power wiring for proper operation and safety.

Connect Yellow wire to constant 12V source (fuse panel or battery)
Connect Red wire to ignition-switched 12V source
Connect Black wire to clean, unpainted metal chassis ground
Connect Blue/White wire to amplifier remote turn-on or power antenna

Tip: Use appropriate fuse (10A recommended) on constant 12V line near power source.

External Device Connections

USB, auxiliary, and Bluetooth device connections.

USB Connection: Connect USB extension cable to rear port for media playback
Auxiliary Input: 3.5mm stereo mini jack for external audio devices
Bluetooth: Built-in for wireless audio streaming and hands-free calling
Remote Input: For optional external control devices

WARNING! Do not exceed USB power specifications (5V, 500mA max).

Antenna Connections

AM/FM antenna connection procedures.

Standard antenna connector: Connect vehicle antenna cable to rear antenna port. Power Antenna: Use Blue/White wire to control power antenna operation. Signal Quality: Ensure secure connection for optimal radio reception.

Safety Precautions

Electrical safety and installation warnings.

Always disconnect battery before installation. Use proper fusing on power lines. Ensure all connections are secure and insulated. Do not route wires near moving parts or hot surfaces. Follow vehicle-specific safety procedures.

Troubleshooting Wiring Issues

Symptom	Possible Cause	Corrective Action
No power	Fuse/power connections	Check fuses; verify Yellow/Red wire connections; ensure proper ground.
No sound from speakers	Speaker wiring	Check speaker connections; verify wire polarity; test speaker operation.
Unit turns off with ignition	Power connections	Ensure Yellow wire connected to constant 12V source.
Poor radio reception	Antenna connection	Check antenna connection; verify power antenna wire if equipped.
USB/Aux not working	Connection/cable	Check cable connections; test with known working devices.

Reset: Disconnect battery for 5 minutes to reset unit if needed.

Service: Contact Kenwood authorized service center for technical support.