1. Product Overview
The Phillips Industries 4-Way Trailer Socket, model 15-400, is a genuine component designed for reliable electrical connection between a tow vehicle and a trailer. This socket facilitates essential lighting functions, ensuring safe towing operations.

Image: Front and back view of the Phillips Industries 4-Way Trailer Socket (Model 15-400).
Key features include:
- Genuine Phillips Industries component, ensuring quality and compatibility.
- Designed for 4-way trailer wiring systems.
- Durable construction for long-lasting performance in various conditions.
- Standardized connection for common trailer lighting functions.
2. What's in the Box
Upon opening the package, you will find the following item:
- 1 x Phillips Industries 4-Way Trailer Socket (Model 15-400)
3. Specifications
| Attribute | Detail |
|---|---|
| Brand | Phillips Industries |
| Model | 4-Way Trailer Socket |
| OEM Part Number | 15-400 |
| Item Weight | 0.25 Kilograms (approx. 8.8 ounces) |
| Vehicle Service Type | Trailer |
| Finish Type | Powder Coated |
| Exterior | Painted |
| Package Dimensions | 4.88 x 3.94 x 2.56 inches |
4. Setup and Installation
Installation of the 4-Way Trailer Socket requires basic automotive electrical knowledge. If you are unsure about any steps, it is recommended to consult a qualified technician.
4.1. Safety Precautions
- Always disconnect the vehicle's battery before beginning any electrical work.
- Wear appropriate personal protective equipment, including safety glasses.
- Ensure all wiring connections are secure and properly insulated to prevent short circuits.
- Refer to your vehicle's owner's manual for specific wiring diagrams and recommendations.
4.2. Mounting the Socket
- Select a suitable, secure location on the tow vehicle, typically near the hitch receiver.
- Ensure the mounting surface is flat and provides adequate clearance for the socket and connected trailer plug.
- Use appropriate fasteners (not included) to securely attach the socket to the vehicle's frame or bumper. The socket features pre-drilled mounting holes for convenience.
4.3. Wiring Connections (Typical 4-Way Flat Wiring)
The 4-way trailer socket typically provides connections for the following functions:
- Brown Wire: Tail/Running Lights
- Yellow Wire: Left Turn Signal/Brake Light
- Green Wire: Right Turn Signal/Brake Light
- White Wire: Ground
Connect the corresponding wires from your vehicle's wiring harness to the terminals on the Phillips 4-Way Trailer Socket. Ensure each connection is crimped or soldered securely and protected with heat shrink tubing or electrical tape.
Note: Wiring colors can vary by vehicle manufacturer. Always verify your vehicle's specific wiring diagram before making connections.
5. Operating Instructions
Once the 4-Way Trailer Socket is correctly installed and wired, connecting your trailer is straightforward.
- Ensure both the vehicle and trailer are parked on a level surface with parking brakes engaged.
- Align the trailer's 4-way flat plug with the vehicle's 4-Way Trailer Socket.
- Gently push the trailer plug into the socket until it is fully seated and secure. The connection should feel firm.
- After connecting, test all trailer lighting functions:
- Turn on vehicle headlights/running lights to check trailer tail lights.
- Activate left and right turn signals to check corresponding trailer lights.
- Apply the vehicle's brake pedal to check trailer brake lights.
- Before driving, ensure all lights are functioning correctly.
5.1. Disconnecting the Trailer
- Ensure both the vehicle and trailer are parked on a level surface with parking brakes engaged.
- Grasp the trailer plug firmly and pull it straight out from the vehicle's socket. Avoid pulling by the wires.
- If the socket has a protective cap, close it to prevent dirt and moisture ingress when not in use.
6. Maintenance
Regular maintenance will help ensure the longevity and reliable performance of your Phillips 4-Way Trailer Socket.
- Cleaning: Periodically inspect the socket for dirt, debris, or corrosion. Clean the electrical pins with a non-abrasive electrical contact cleaner and a soft brush.
- Lubrication: Apply a small amount of dielectric grease to the electrical pins to protect against corrosion and ensure smooth connections.
- Inspection: Check for any signs of damage to the socket housing, wires, or pins. Ensure the mounting is secure.
- Storage: When not in use, keep the socket covered with its protective cap (if applicable) to shield it from elements.
7. Troubleshooting
If you experience issues with your trailer lighting, follow these basic troubleshooting steps:
| Problem | Possible Cause | Solution |
|---|---|---|
| No trailer lights working | Blown fuse in tow vehicle; Poor ground connection; Damaged wiring. | Check vehicle's fuse box for trailer light fuses and replace if necessary. Ensure trailer plug is fully seated. Inspect ground wire connection on both vehicle and trailer. Check for visible damage to wiring. |
| Specific trailer light (e.g., turn signal) not working | Burnt out bulb on trailer; Corroded pin in socket/plug; Loose wire connection. | Check and replace trailer bulb. Clean corresponding pins on both socket and plug. Verify wire connection for that specific function. |
| Intermittent light function | Loose connection; Corrosion on pins; Damaged wire insulation. | Ensure plug is securely seated. Clean and apply dielectric grease to pins. Inspect wiring for frayed or exposed sections. |
If these steps do not resolve the issue, it is recommended to seek assistance from a professional automotive electrician.
8. Warranty and Support
For information regarding the warranty of your Phillips Industries 4-Way Trailer Socket, please refer to the official Phillips Industries website or contact their customer support directly. Warranty terms and conditions may vary.
For additional product information or support, you may visit the official Phillips Industries store on Amazon: Phillips Industries Amazon Store.





