/ Technical Support / By Victory Technical Team (Zhuji Aoke Factory)
The connection between a tractor and a trailer is the lifeline of a heavy-duty truck. It carries the air that stops the vehicle and the electricity that lights it up. Whether you call it a “3-in-1 Kit,” a “Power Line Assembly,” or “Air & Cord Combo,” choosing the right kit is vital for road safety.
At Victory Technology, we manufacture thousands of these DOT-compliant kits annually. Here are the answers to the most common questions we receive from fleet managers and distributors.
🔴 Section 1: What is a 3-in-1 Kit? (Basics)
Q1: What is included in an Air Hose & Cord Kit?
A standard 3-in-1 kit combines three critical lines into one spiral-wrapped bundle:
Red Air Hose: Emergency (Supply) Line – supplies air to the trailer tanks.
Blue Air Hose: Service (Control) Line – applies the brakes when you press the pedal.
Electrical Cable: (Typically Yellow or Green ABS Cable) – powers the lights, ABS, and turn signals.
Includes: Gladhands and Buffalo Plugs (7-Way).
Coiled (Spiral): The industry standard. It retracts automatically to prevent dragging on the deck plate. Best for standard semi-trucks.
Straight: Used for longer reaches or specific sliding fifth wheel setups where coils might over-stretch. Requires a “pogo stick” or heavy-duty springs to manage.
To prevent deadly cross-connections:
🔴 Red = Emergency.
🔵 Blue = Service.
🟡/🟢 Yellow/Green = Electrical (ABS/EBS).
It transmits power and signals from the tractor to the trailer for:
Tail lights, brake lights, and turn signals.
ABS (Anti-Lock Braking System) and EBS modules.
Air Hoses: Typically PA12 (Nylon) for stiffness and memory, or PU (Polyurethane) for cold-weather flexibility.
Electrical Cable: High-grade PVC jacket with 100% Copper wiring (Victory does NOT use cheap CCA aluminum wire).
Fittings: Brass or Zinc-plated steel for corrosion resistance.
Yes. All our air hoses meet SAE J1402 & DOT FMVSS 106 standards. They typically have a working pressure of 150 PSI and a burst pressure of 900+ PSI.
It depends on the material.
Budget kits: May become stiff and crack in freezing temps.
Victory “Arctic Grade” kits: Remain flexible down to -40°C (-40°F) thanks to special plasticizers in the Nylon/PU blend.
Yes. The cable jacket is sealed, and the 7-Way Plugs (Buffalo Plugs) feature weather-tight seals to prevent corrosion at the connection points.
The most common lengths are 12 ft and 15 ft.
12 ft: Standard day cabs.
15 ft: Sleepers or trucks with sliding fifth wheels (provides extra slack for turns).
Tangling destroys hoses.
Use a 3-in-1 Kit: The spiral wrap keeps lines together.
Spring Supports: Use a “Tender Spring” or “Pogo Stick” to suspend the lines high above the deck plate.
Over time, Heat (from the engine/exhaust) and UV Exposure breakdown the polymer’s memory. Once a coil sags and touches the deck plate, it must be replaced before it chafes through.
Typically every 2–4 years, or immediately if you see:
Cracks in the hose jacket.
Kinks that restrict airflow.
Exposed copper wires.
Technically yes, but we recommend replacing the full kit. If one hose has failed due to age/UV, the others are likely close to failure too. Replacing the whole assembly ensures balanced tension.
Mostly, yes. The Gladhand connections and 7-Way Plugs are universal across North America. However, you must ensure the length (12ft vs 15ft) is correct for your turning clearance.
Directly. A leak in the Blue line means weaker braking force. A leak in the Red line can cause the trailer emergency brakes to lock up unexpectedly.
A high-quality aftermarket kit (like Victory’s) that meets SAE & DOT standards performs equally to OEM but at a much lower cost. Always check for the DOT stamp on the hose.
🏭 Factory Pro Tip: Always store spare kits in a dark, cool place. UV light from the sun is the #1 enemy of stored Nylon tubing.
