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Parts Needed to Re-Wire 18 Foot Car Hauler Trailer with 7-Way Connector


Im having trouble finding everything I need. Looking to re do all the wiring on a 18foot car hauler trailer with brakes on one axle. So I need all wiring with round, 7 pin connector, I should be able to use existing lights. And also any type of manual you would have to help me with wiring brakes since Im unfamiliar with that. Thanks.


Expert Reply:

To re-wire your 18 foot car hauler with electric brakes on one axle, I recommend using a wiring junction box like # 38656 in order to make the connections from the lights and brakes. Then for a 7-way trailer plug, you can use the Hopkins # H20046. This connector has an 8 foot lead. The shorter 6 foot # H20044 or 4 foot # H20043 trailer connectors are also available.

I recommend using a circuit tester like # 40376 to determine the functions for any wires that are not known, as just using the wire colors may not be reliable.

Next you will need ring terminals to make all the needed connections in the junction box for your lights and brakes. For 10-12 gauge wires you will use # DW05741-1 and for 14-16 gauge wires you will use # DW05702-1.

You will then use 10 gauge wire like # 10-1-1, which is sold by the foot, to connect from the electric brakes on your trailer to the junction box. Either of the two wires coming from each brake assembly can be used for grounding to the trailer frame because brakes are non-polarized. You will use the other wire for power. You can use butt connectors # 05732-2 for the brake circuit wire. I have attached an electric brake installation video for you to review. Right around the 5:23 mark in the video you can see the wire connections being made.

I have also included a helpful article on trailer wiring as well as an installation video for the junction box that you may find helpful.

expert reply by:
Chris R

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