Can Interior Lights on Trailer be Wired to Work When Connected to 2005 Ford F-250 12V Power

Question:

Hi, I just purchased a 2016 Adam 2-horse bumper pull trailer, model 710A-DR. Im pulling with a 2005 Ford F250 which has a 7 way plug. Everything on the trailer is currently working except the interior lights. The trailer is brand new demo and the dealer says these trailers are meant to be hot wired so that the lights can operate even when there is no key in the ignition. If this is true, then does that mean the interior lights wouldnt work with the current 7 way plug when the key IS in the ignition? Thank you!!!

asked by: April S

Helpful Expert Reply:

The pin in the 1 o'clock position (see attached picture) on the 7-Way of your 2005 Ford F-250 should have a constant 12V of power running to it as long as your trailer connector is plugged into your truck. If you wire your interior lights to this contact 12V power then you will have running lights for your trailer as long as that pin has 12V power.

Some vehicles are equipped so that when the vehicle is turned off and the key is removed that wire does not continue to receive signal. you can simply test this by leaving the key in the ignition and testing the lights in your trailer once you have hardwired them in to your trailer connector.

If you would like to bypass the wiring on your truck you can use 10 Gauge Wire # 10-1-1, Butt Connectors # DW05745-5, a Circuit Breaker # 9510, and a ring terminal like part # 44-5310A or part # DW05705-1. You will simply need to run this wire from the positive terminal on your battery to the 12V pin on the 7-Way of your F-250.

Keep in mind that this option will provide constant power to that 12V pin so if you were to leave your trailer hooked up overnight and you forgot to turn some lights off in your trailer it could result in a dead battery. It may be useful to have a battery charger like part # CTEK56353 handy for such an event.