TRAILER HITCHES – Wiring

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ELECTRICAL WIRING—AN IMPORTANT ASPECT WHEN SELECTING YOUR TRAILER HITCH

In order to “legally” tow a trailer, proper wiring must be installed between your vehicle and your trailer to provide it with functional rear lights, turn signals and braking lights.

Several types of electrical wiring are available to meet various towing requirements. These are the main types:

4-PIN WIRING WITH FLAT PLUG

The 4-pin wiring with flat plug (connector) meets basic requirements including three light-related functions:

  • Right-turn signal and brake light (green wire)
  • Left-turn signal and brake light (yellow wire)
  • Tail lights, license plate and side marker (brown wire)
  • Ground wire (white wire)

5-PIN WIRING WITH FLAT PLUG

The 5-pin wire with flat plug (connector) has the same features as the 4-pin wiring but includes an extra blue wire that can be connected to the trailer’s brake or an auxiliary source of power. This wiring is often used for trailer tents, utility trailers or boat trailers.

  • Right-turn signal and brake light (green wire)
  • Left-turn signal and brake light (yellow wire)
  • Tail lights, license plate and side marker (brown wire)
  • Ground wire (white wire)
  • Trailer brake or auxiliary power source (blue wire)

6-PIN WIRING WITH RECTANGULAR PLUG

This 6-pin wiring with a rectangular plug (connector) that measures 3/4″ by 1″ is often used for small motorcycle, snowmobile or utility trailers.

  • Right-turn signal (green wire)
  • Left-turn signal (yellow wire)
  • Tail lights (brown wire)
  • Ground wire (white wire)
  • Trailer brake and auxiliary power source (red and blue wires)

6-PIN WIRING WITH ROUND PLUG

The 6-pin wiring with a 1″ diameter round plug (connector) includes one or two additional wires for light-related functions such as back up lights, brake control or a 12-volt auxiliary source of power. This wiring is used for horse, car or landscaping equipment trailers.

7-PIN WIRING WITH ROUND PLUG

This 7-pin wiring with a 1 5/8” diameter round plug (connector) is the most popular for heavy-load towing. It contains an additional wire for back up lights or an auxiliary source of power. This wiring is used for horse, car, landscaping equipment, boat and construction material trailers.

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