Wiring A Trailet Horse Trailer For Lights, Fans, And An Electric Trailer Jack

Updated 01/04/2024 | Published 12/29/2023

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Question:

Hello. I am wiring up my Trailet Horse trailer with an aux battery, new junction box and a disconnect switch so that we can run new lights, fans, and camera while connected to the truck or disconnected temporarily. I also need to jack to operate from the battery as well. I have attached a diagram of what I am thinking but the actual wiring diagram - I’m a little unsure, especially when it incorporates the disconnect and breakaway switch. Can u give me some pointers as to how to wire the disconnect and breakaway? Should fans and such run to the battery or the hot lead from the junction box? Thanks.

asked by: Scott E

Expert Reply:

All clearance lights, tail lights, and the camera should run through to the 7-way connector junction box so that they are powered when connected to the tow vehicle. The breakaway switch will also need to be ran to this junction box in order to activate the brake assemblies in the event of a breakaway.

The fans and any internal lights or appliances should be ran to a DC distribution panel and then ran to the trailer battery for power. A small DC distribution panel can be picked up from your local hardware store and will provide fused protection for your appliances. The jack can also be wired directly to the trailer battery with a suitable amperage in-line fuse to protect the motor.

To keep the trailer battery charged up you can run a charge line from the 12v hot lead in the 7-way junction box to the battery. You'll need some 10 gauge wire # 10-1-1 and an in-line circuit breaker # PK54230 for this. This will charge the battery while the truck is running but will be limited to the output of the 7-way on the tow vehicle, which is typically pretty low amperage, usually around 10-15 amps.

If you want to charge the trailer battery while parked somewhere with 15 amp 110v service then you can install the Bright Way Switch Mode Battery Charger # BRW77FR and pick up an extension cord to complete the connection.

If you want a bit more of a dedicated charge while towing you can also install the Redarc In-Vehicle BCDC Battery Charger # RED96FR. This uses the tow vehicle's alternator to charge the trailer battery while the tow vehicle is running. This will require a fuse # 331-FK40 at both the tow vehicle and trailer battery for protection.