1. Bevezetés
The CURT 56404 Vehicle-Side Custom 4-Pin Trailer Wiring Harness provides a simple, plug-and-play electrical solution for towing a trailer with select Audi Q5 vehicles. This T-connector style harness integrates directly into your vehicle's existing electrical system, eliminating the need for cutting, splicing, or soldering during installation. It delivers a standard 4-way flat connector, enabling connection for trailer tail lights, brake lights, and turn signals, ensuring reliable and safe trailer lighting.
2. Termék végeview & Jellemzők
The CURT 56404 wiring harness is engineered for vehicle-specific fit and optimal performance. Key features include:
- Könnyű telepítés: Designed for a plug-and-play setup, connecting directly into your vehicle's factory wiring without cutting or splicing.
- Standard 4-Pin Connector: Provides a universal 4-way flat connector socket for trailer tail lights, brake lights, and turn signals.
- Vehicle-Specific Design: Custom-fit for specific years of the Audi Q5, ensuring seamless integration.
- Megbízható teljesítmény: Built with surface mount technology (SMT) circuitry, which generates less heat and offers optimal light intensity and durable performance.
- Porvédő huzat mellékelve: Comes with a rubber dust cover to protect the 4-way flat connector from dirt, moisture, and corrosion when not in use.

1. ábra: Egy overview of the CURT 56404 wiring harness, displaying the main control module, vehicle-specific connectors, 4-pin flat trailer connector, fuse holder, and wiring.

Figure 2: Diagram highlighting key features: a sealed, epoxy-filled enclosure for the control module, plug-and-play connectors for vehicle integration, and a standard trailer wiring output.
3. Beállítás és telepítés
Before beginning installation, ensure your vehicle is turned off and the parking brake is engaged. It is recommended to disconnect the vehicle's battery to prevent electrical shorts.
- Access Vehicle Wiring: Locate the taillight wiring access points in your Audi Q5. This typically involves removing interior trim panels in the rear cargo area or trunk to expose the vehicle's taillight harness connectors. Refer to your vehicle's owner's manual for specific panel removal instructions.
- Connect T-Connectors: The CURT harness features vehicle-specific T-connectors. Disconnect the factory taillight harness connectors and insert the corresponding CURT T-connectors in-line. Ensure a secure and tight connection.
- Mount Control Module: Find a dry, secure location within the vehicle's rear cargo area to mount the control module. Use the provided double-sided tape or zip ties to firmly attach the module, ensuring it is protected from moisture and vibration.
- Route 4-Pin Connector: Route the 4-way flat connector to the exterior of the vehicle, near the trailer hitch. Ensure the wiring is protected from sharp edges, heat, and moving parts. Use zip ties to secure the wiring along the vehicle's frame or existing wire harnesses.
- Connect Power Wire: Connect the power wire (typically red or black with an in-line fuse holder) to the vehicle's battery or another suitable power source, as specified in the detailed instructions provided with the product. Ensure the fuse is installed correctly.
- Csatlakoztassa a földelő vezetéket: Securely attach the white ground wire to a clean, unpainted metal surface on the vehicle's frame using the provided ring terminal and a self-tapping screw.
- Teszt csatlakozások: Reconnect the vehicle battery. Use a trailer or a trailer light tester to verify that all trailer lights (tail lights, brake lights, turn signals) function correctly.
- Telepítse újra a trim-et: Once all connections are verified, reinstall any removed trim panels.
Video 1: Official installation video for the CURT 56404 Vehicle-Side Custom 4-Pin Trailer Wiring Harness, demonstrating the plug-and-play installation process for compatible Audi Q5 models.

Figure 3: Various components of the circuit protected converter system, such as a fuse, ring terminal, butt connectors, and zip ties, provided for installation.
4. Működés
Once installed, the CURT 56404 harness provides a functional 4-way flat connector for your trailer. To operate:
- Remove the dust cover from the 4-way flat connector.
- Connect the trailer's 4-way flat plug to the vehicle's 4-way flat socket. Ensure the connection is firm and secure.
- Verify that all trailer lights (tail lights, brake lights, turn signals) are working correctly before driving.

4. ábra: Közeli kép view of the 4-way flat trailer wiring connector, showing the male and female ends designed for connecting to a trailer.

Figure 5: A schematic diagram illustrating the pin configuration of a 4-way flat vehicle end plug, indicating its standard output.
5. Karbantartás
Proper maintenance ensures the longevity and reliability of your wiring harness:
- Porvédő: Always use the provided rubber dust cover on the 4-way flat connector when it is not in use. This protects the terminals from moisture, dirt, and road debris, preventing corrosion.
- Csatlakozások ellenőrzése: Periodically inspect all electrical connections for corrosion, loose wires, or damage. Clean any corroded terminals with a wire brush and electrical contact cleaner.
- A vezetékek integritása: Check the entire length of the wiring for any signs of chafing, cuts, or pinches, especially where it passes through the vehicle's body or near moving parts. Repair any damage immediately.
- Biztosíték ellenőrzése: If trailer lights fail to operate, check the in-line fuse in the power wire. Replace it with a fuse of the same amperage if blown.

Figure 6: A hand demonstrating how to attach the included rubber dust cover to the 4-way flat connector, protecting it from elements when not in use.
6. Hibaelhárítás
If you experience issues with your trailer lighting, consider the following troubleshooting steps:
- Nincs utánfutó világítás: Check the vehicle's fuses and the in-line fuse on the CURT harness. Ensure all T-connector connections are secure. Verify the ground wire connection is clean and tight.
- Intermittent Lights: Inspect all connections for looseness or corrosion. Check for damaged wiring that might be causing intermittent contact.
- Incorrect Light Function: Ensure the trailer's wiring is correctly matched to the 4-way flat connector. Test the vehicle's lighting functions (tail, brake, turn) independently to confirm they are working correctly before connecting the trailer.
- Vehicle-Specific Considerations: Some vehicles may require the tailgate or trunk to be fully closed for trailer lights to function. Consult your vehicle's owner's manual for any specific towing requirements.
7. Műszaki adatok
| Specifikáció | Érték |
|---|---|
| Márka | KURTA |
| Modellszám | 56404 |
| Tétel súlya | 1.26 font |
| Termék méretei | 7 x 2 x 2 hüvelyk |
| Csatlakozó típusa | 4-Pin Flat (Vehicle-Side) |
| Járműkompatibilitás | Select Audi Q5 models |
8. Garancia és támogatás
For warranty information or technical support regarding your CURT 56404 Vehicle-Side Custom 4-Pin Trailer Wiring Harness, please refer to the documentation included with your product or visit the official CURT website. You may also contact CURT customer service directly for assistance.





