What Vehicle Fuse Controls Trailer Interior Lighting and Can it be Bypassed

Question:

What fuse controls the interior lights to a trailer? My exterior lights work but can’t seem to figure out why none of my interior lights work.

asked by: Angie

Expert Reply:

On a truck the circuit that would control the interior lights of a trailer would be the 12-volt accessory trailer circuit. Sometimes this circuit doesn't come on unless the vehicle is running or with the key on so you might try doing that as well to determine if the circuit is "working."

One solution that we recommend for a lot of people with issues with this circuit is to bypass the vehicle wiring and run a wire directly from the battery of the truck to the 7-way so that you can have it active all the time and not mess with trying to track down confusing OEM wiring issues. To do that you'd want 10 gauge wire like part # 10-1-1 (sold by foot) ran through a breaker like part # 9510 and you'd be set.

The pin on your 7-way that controls this circuit is in the 1:00 position as you face the opening. See picture.

expert reply by: Jameson C