1. Introduction
This manual provides comprehensive instructions for the installation, operation, and maintenance of your CURT 99303 Class 3 Trailer Hitch and 4-Pin Wiring Harness. This complete towing kit is designed to outfit select Ford Explorer and Ford Police Interceptor Utility vehicles for towing. It features a custom-fit hitch with a 2-inch receiver and a wiring harness that connects directly to existing factory wiring, eliminating the need for splicing.
The CURT 99303 is engineered for dependable strength, rated for up to 4,000 lbs. Gross Trailer Weight (GTW) and 400 lbs. Tongue Weight (TW), with higher capacities when used with a weight distribution system. Its durable construction includes a co-cured liquid Bonderite and powder coat finish for superior rust, chip, and UV resistance.
2. Safety Information
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
- Always read and understand all instructions before installation and operation.
- Ensure all components are securely fastened before towing. Regularly inspect the hitch and wiring for wear or damage.
- Do not exceed the lowest-rated towing component's capacity (vehicle, hitch, or ball mount).
- Wear appropriate personal protective equipment (PPE) during installation, including safety glasses and gloves.
- If you are unsure about any part of the installation process, consult a qualified professional.
3. Package Contents
The CURT 99303 package includes the following components:
- Class 3 Trailer Hitch (2-inch receiver)
- 4-Pin Wiring Harness
- Installation Hardware (bolts, washers, nuts as required)
This image displays the main components of the CURT 99303 kit, including the black powder-coated trailer hitch with a 2-inch receiver and the accompanying 4-pin wiring harness.
4. Specifications
| Feature | Specification |
|---|---|
| Model Number | 99303 |
| Brand | CURT |
| Receiver Size | 2-inch x 2-inch |
| Gross Trailer Weight (GTW) | 4,000 lbs. |
| Tongue Weight (TW) | 400 lbs. |
| Weight Distribution (WD) Capacity | 5,000 lbs. |
| Weight Distribution Tongue Weight (WDTW) | 500 lbs. |
| Material | Alloy Steel |
| Finish Type | Powder Coated (Co-cured liquid Bonderite and powder coat) |
| Wiring Harness Type | 4-Pin Flat Vehicle End |
| Vehicle Service Type | Trailer |
| Product Dimensions | 54 x 21 x 7.2 inches |
| Item Weight | 36.1 Pounds |
This image visually confirms the 2-inch receiver tube size, indicating compatibility with standard 2-inch hitch accessories.
5. Installation Guide
This section outlines the general steps for installing the CURT 99303 trailer hitch and wiring harness. Specific vehicle models (Ford Explorer, Ford Police Interceptor Utility) may have unique requirements; always refer to the detailed instructions provided with the product packaging or a vehicle-specific installation guide.
5.1. Trailer Hitch Installation
- Prepare the Vehicle: Park the vehicle on a level surface and engage the parking brake. For easier access, it may be necessary to raise the vehicle using a lift or jack stands. Lowering the exhaust temporarily might also be required for some models.
- Locate Mounting Points: Identify the frame mounting points on your vehicle. These are typically pre-drilled holes in the vehicle's frame.
- Position the Hitch: Carefully lift the trailer hitch into position, aligning the mounting holes on the hitch with the vehicle's frame holes. It is recommended to have assistance for this step due to the weight of the hitch.
- Secure the Hitch: Insert the provided hardware (bolts, washers, nuts) through the aligned holes. Hand-tighten all fasteners to ensure proper alignment before final tightening.
- Final Tightening: Using appropriate tools, tighten all fasteners to the torque specifications provided in the detailed installation instructions. Ensure all bolts are securely fastened.
- Reinstall Components: If any vehicle components (e.g., exhaust) were removed or lowered, reinstall them securely.
This close-up view highlights the standard 2-inch x 2-inch hitch receiver, ready to accept various towing accessories like ball mounts, cargo carriers, or bike racks.
5.2. Wiring Harness Installation
The CURT 4-pin wiring harness is designed for a plug-and-play installation, requiring no cutting or splicing of wires.
- Locate Vehicle Connectors: Identify the factory wiring connectors on your Ford Explorer or Police Interceptor Utility. These are typically located near the taillight assemblies or under the vehicle's rear bumper.
- Connect Harness: Plug the corresponding connectors of the CURT wiring harness directly into the vehicle's factory wiring. Ensure a secure and snug connection.
- Route Wiring: Route the 4-pin flat connector to a convenient location near the trailer hitch receiver, ensuring it is protected from heat, sharp edges, and moving parts. Use the included zip ties or other fasteners to secure the wiring.
- Test Functionality: Before towing, connect a trailer or a trailer light tester to the 4-pin connector and verify that all trailer lights (running lights, brake lights, turn signals) function correctly.
This image shows the standard 4-pin flat connector, which provides essential lighting functions for a trailer, including running lights, brake lights, and turn signals.
The included dust cover protects the 4-pin connector from dirt, moisture, and corrosion when not in use, extending the life of the wiring harness.
6. Operation
Once installed, your CURT trailer hitch and wiring harness are ready for use. Always ensure proper connection and safety checks before each towing operation.
6.1. Connecting a Trailer
- Attach Ball Mount: Insert a compatible 2-inch ball mount (sold separately) into the hitch receiver and secure it with a hitch pin and clip.
- Connect Trailer Coupler: Lower the trailer coupler onto the hitch ball and secure the coupler latch. Ensure the coupler is fully seated and locked.
- Attach Safety Chains: Cross the trailer's safety chains under the trailer tongue and attach them to the designated chain loops on the hitch.
- Connect Wiring: Plug the trailer's 4-pin connector into the vehicle's 4-pin wiring harness.
- Test Lights: Verify that all trailer lights (running lights, brake lights, left and right turn signals) are functioning correctly before driving.
6.2. Towing Considerations
- Always adhere to your vehicle's towing capacity and the hitch's maximum ratings.
- Distribute trailer load evenly to maintain proper tongue weight.
- Adjust driving habits when towing, allowing for increased stopping distances and wider turns.
- Regularly check tire pressure on both the tow vehicle and trailer.
7. Maintenance
Proper maintenance ensures the longevity and safe operation of your CURT trailer hitch and wiring harness.
- Regular Inspection: Periodically inspect the hitch for signs of rust, cracks, bends, or other damage. Check all bolts and fasteners for tightness.
- Clean Receiver: Keep the inside of the hitch receiver clean and free of debris to ensure easy insertion of ball mounts and accessories.
- Wiring Care: Inspect the wiring harness for frayed wires, damaged insulation, or corroded terminals. Keep the 4-pin connector clean and use the dust cover when not in use.
- Lubrication: Apply a thin layer of grease to the hitch ball (if applicable) and inside the receiver tube to prevent rust and facilitate connection.
- Finish Protection: The co-cured liquid Bonderite and powder coat finish provides excellent protection. Clean with mild soap and water as needed. Avoid harsh chemicals that could damage the finish.
This image illustrates the process of applying the dual-coat finish, where hitch components are submerged in a liquid Bonderite solution before powder coating, providing superior corrosion resistance.
8. Troubleshooting
This section addresses common issues you might encounter with your trailer hitch and wiring harness.
| Problem | Possible Cause | Solution |
|---|---|---|
| Trailer lights not working | Loose wiring connection, blown fuse, corroded terminals, faulty trailer lights. | Check all connections on the wiring harness and trailer. Inspect vehicle's fuse box for blown fuses. Clean any corroded terminals. Test trailer lights directly if possible. |
| Hitch difficult to install | Misalignment with vehicle frame, exhaust interference. | Ensure proper alignment with vehicle's pre-drilled holes. Temporarily lower exhaust if necessary (refer to vehicle-specific instructions). Consider professional installation. |
| Excessive sway when towing | Improper weight distribution on trailer, insufficient tongue weight, worn suspension components. | Adjust trailer load to achieve proper tongue weight (typically 10-15% of GTW). Consider a weight distribution hitch if not already using one. Inspect vehicle and trailer suspension. |
9. Warranty Information
Specific warranty details for the CURT 99303 Class 3 Trailer Hitch and Wiring Harness are typically provided with the product packaging or can be found on the official CURT Manufacturing website. Generally, CURT products are backed by a limited lifetime warranty for the hitch structure and a limited warranty for the finish and electrical components. Please retain your proof of purchase for warranty claims.
For the most current and detailed warranty information, please visit the CURT Manufacturing website.
10. Customer Support
If you require further assistance with your CURT 99303 product, please contact CURT customer support. Contact information can typically be found on the official CURT Manufacturing website or within the product packaging.
You may also find helpful resources, including installation videos and FAQs, on the CURT website: www.curtmfg.com.