How to Power Trailer Dome Light When Not Connected to Tow Vehicle

Updated 03/18/2024 | Published 03/22/2015

Question:

Is there a way to power the Cargo Trailer Dome Lights when not hooked up to a vehicle? Trailer has an auxiliary battery and brake-away brake system. Could I increase battery size, then wire the trailer so that the battery would work to power the break-away and when not hooked-up to vehicle, power the dome lights? Thank You

asked by: Dennis R

Expert Reply:

The only way you could power interior dome lights on a trailer without it being connected to a tow vehicle would be to power the lights with a battery like a breakaway battery.

How you choose to wire up the batteries will in the end be up to you, but since breakaway batteries need to be charged up when you are towing I would be careful not to drain the battery with the dome light.

expert reply by: Jameson C

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Mike B.

3/16/2024

Is ther an available harness tha I could plug into the tow cable to my cargo trailer and then connect to an external 12v deep cycle battery to power the interior lights when the trailer isn’t connected to my truck?

Jameson C.

3/18/2024

@MikeB While there isn't a harness designed specifically for that you could make one pretty easily. What you'd need is a 7-way socket like the part # PK12703 and then wiring like the part # 10-2-1 to run from the connector to the battery and you'd be set. The wire I mentioned is a double bonded two wire 10 gauge wire setup so it would cover power and ground.