Check N Tow™ 7/4-Way Plug - Modular Trailer Light Tester
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The Smallest, Most Capable Trailer Light Tester
The Check N Tow™ is the shop-grade diagnostic tool trusted by haulers, mechanics, and fleet operators. At just 11" × 5" × 5", it’s one of the smallest fully functioning testers available—compact enough for your toolbox, yet powerful enough to handle professional workloads.
Why it’s better than other testers:
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🔒 Resettable Protection: Built with three circuit breakers (not fuses) to protect every function—no more downtime replacing blown fuses.
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💡 Flexible Testing: Individual switches let you test any light or combination at once for fast, accurate diagnostics.
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🚦 True Vehicle Simulation: Dual relays and an LED flasher support both LED and incandescent bulbs, mimicking real on-road behavior including brake/turn signal override.
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🔋 Battery Compatibility: Runs on the 18V–36V Milwaukee and DeWalt batteries you already own. Swap adapters to support other platforms.
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🔌 Connector Versatility: Standard with both 7-blade and 4-way connectors. Works with 6-pin using an adapter.
Bottom line: The Check N Tow™ isn’t just another trailer tester—it’s a compact, professional-grade solution designed to make trailer light testing faster, easier, and more reliable than ever.
Tests All 7 Functions Independently:
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Left Turn (flashing)
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Right Turn (flashing)
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Brake Lights (with signal override simulation)
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Tail Lights
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Electric Brakes
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Reverse Lights
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12V Auxiliary Power
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Features:
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Realistic Vehicle Signal Simulation
Unlike basic testers, Check N Tow mimics how real vehicle lighting behaves — brake lights stay lit on the opposite side when signaling while braking, giving you a true-to-life test every time. -
Modular Battery Adapter System
Choose the battery brand you already use (Milwaukee M18 or DeWalt 20V MAX). Your selected adapter is installed directly to your tester — no wires to modify. -
Easily Swappable Battery Mounts
Change brands later? Just order a new adapter, unscrew four bolts, and swap it out in minutes. Future support for additional battery types is in development. -
On-Board Digital Voltage Display
Monitor 12V power output live with a crisp, backlit voltage readout. -
Portable & Cordless
No need to plug in — take it right to the trailer, job site, or roadside.
Built for Real-World Use:
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Standard 7-Way Blade Connector – Works with RVs, equipment, utility trailers, and more.
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Industrial Toggle Switches – Control each function with a tactile, illuminated switch.
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High-Strength Housing – 3D-printed with reinforced composite plastic for durability.
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Color-Coded Labels – Instantly see what you're testing — even in low light.
Specs:
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Material: Impact-resistant 3D-printed PETG Housing
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Power Source: Modular Milwaukee M18 or DeWalt 18-48V battery (battery not included)
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Dimensions: Approx. 11” x 5” x 5”
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Connector Type: 7-Way RV Blade and 4 Way Straight
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Assembled In: USA
Whether you're a weekend warrior, fleet mechanic, or trailer builder — this tool saves time, avoids frustration, and ensures safety every trip.
Check N Tow Before You Go — Order Yours Today!
This device is a game changer! It’s so easy to use and anyone can use it. I use it at my camp site to help campers diagnose and verify their lights are working.
A smart way to quickly test your trailers lights. I love how I can simply use my Milwaukee battery to power the unit. Couldn’t be happier with my purchase!
This thing is Awesome. I love how I can simulate braking
while using the directionals. This was a great feature and goes beyond just
checking the lights, also love how the directionals flash and click just like
my vehicle!
This device is worth every penny. It’s simple to use, light weight and works seamlessly. Great investment for any trailer hauler.
