Seachoice 7-Way Round to 5-Way Flat Cable Adapter – 18" Boat Trailer (50-13821)
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You have 30 days to request a return. All sale items are final sale.
Overview
The Seachoice 50-13821 7-Way Round to 5-Way Flat Cable Adapter is an 18-inch wired adapter that connects a vehicle's 7-way round blade connector to a boat trailer's 5-way flat plug. The 18-inch cable provides flexible routing between the tow vehicle's hitch receiver and the trailer tongue, making it easier to connect in tight spaces or when the trailer plug doesn't quite reach the vehicle outlet. No wiring modifications are required — simply plug in and go.
Features
- Adapts a 7-way round vehicle connector to a 5-way flat trailer plug
- 18-inch cable for flexible routing and easier connection at the hitch
- Plug-and-play installation — no cutting, splicing, or rewiring required
- Supports standard trailer lighting: running lights, brake lights, turn signals, and ground
- Designed specifically for boat trailer applications
- Durable construction for marine and road trailering environments
Best Use Cases
- Towing a boat trailer with a 5-way flat connector from a truck or SUV with a factory 7-way round blade outlet
- Installations where the trailer plug falls short of the vehicle outlet and a cable-style adapter provides the needed reach
- Replacing a worn or damaged 7-way to 5-flat cable adapter on an existing tow setup
Connector Compatibility
- Vehicle side: 7-way round blade connector (standard on most trucks and SUVs)
- Trailer side: 5-way flat connector (common on boat trailers with a reverse light or auxiliary circuit)
- Cable length: 18 inches
Related Trailer Connector Adapters
- Seachoice 7-Way to 4/5-Way Trailer Connector Adapter (50-13811) — compact plug-style adapter for 4 or 5-flat trailers
Parts Desk Insights
Best Use Case: This is the right adapter when a customer's boat trailer uses a 5-way flat connector and their tow vehicle has a 7-way round outlet — and they need the extra reach of an 18-inch cable to make the connection comfortably at the hitch. It is particularly useful on longer truck beds or when the trailer tongue is short and the plug doesn't reach a compact adapter at the receiver.
vs. Compact Adapter: If the customer doesn't need the extra cable length, the Seachoice 7-Way to 4/5-Way Compact Adapter (50-13811) is a simpler, lower-profile solution for the same connector mismatch.
Fitment Note: This adapter handles lighting circuits only (running lights, brake lights, turn signals, ground). It does not pass through the 7-way's electric brake, auxiliary power, or reverse light circuits to the trailer. If the customer's trailer has electric brakes or requires auxiliary power, a full wiring harness solution will be needed.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.