Review on Curt Manufacturing 58904 Towed Vehicle Harness by Suhas Payton

When the vehicle being towed applies the brakes or headlights, power is applied to the RV headlights. Regardless of whether the RV is a computer/multiplex system, it powers the output of the RV lighting system and illuminates the RV lights from the towed vehicle. Or while driving, when the onboard power supply of both vehicles supplies the headlights of the motorhome with power. Diodes only block power from the RV to the towed vehicle's electrical/computer systems.