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Instructions for Completely Rewiring a 14 Foot Tandem Axle Dump Trailer


We have a dump trailer and I was wondering if rewiring the trailer is something that is simple to do and what I would need. Thanks for the info. It is a double axle with magnetic brakes. I believe that it is a 7 way bladed plug. 14 feet long.


Expert Reply:

Rewiring your 14 foot dump trailer is pretty straight forward. I would start with a 20 ft. Wishbone 4-Way Trailer Wiring Harness, # A20WB, to provide wiring for the stop turn and tail lights on your trailer. We have a video detailing how to install this type of harness for you to review, see link.

Next, I would use the RV-Style Trailer Connector, # PK12706, and remove the 4-Way connector from the 4-Way harness and install the wires in the proper locations in the 7-Way connector. Our wiring page, see link, has photos that detail the wiring configuration of the 7-Way RV trailer connector for you to review.

Next, you will need to wire the trailer brakes. I would use an appropriate length of the Double Bonded 10 gauge wire, # 10-2-1, and run wires from the trailer brake output terminal in the 7-Way connector, # 2, and the ground wire coming out of the 7-Way connector, to each brake magnet. Run the 10 gauge wires down one side of the trailer and T off to go to the brake magnets on the other side.

Next, run a 10 gauge wire from the 12 volt power terminal, # 4, in the 7-Way to the positive post of the battery that provides power for the hydraulic pump on your dump trailer. Make sure the battery is grounded to the trailer frame and that you have a ground wire attached to the trailer frame from the ground in the 7-Way connector. This wire will then help maintain the trailer mounted battery charge when the vehicle is running and the trailer is plugged in.

Finally, your dump trailer may have a breakaway kit installed. You will need to make sure the wiring for the breakaway is ran correctly for it to function properly. Since your trailer has a battery for the hydraulic pump, the battery may be utilized for the breakaway system also. I have added links to an installation video that shows a breakaway kit being installed, and a drawing that shows how a typical breakaway is wired.

To make the installation more professional looking and protect the wiring you may want to use some wire loom, # 459075-1, metal loom clamps, # A0500, and some ring terminals, # DW05705-1.

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