Roadmaster Smart Diodes For LED Bulbs - 2-Pack|789

Diodes are frequently used in wiring kits to prevent the backflow of current to the electrical system of the towed vehicle or motorhome. However, many newer vehicles now use a multiplex wiring system, whereby multiple electrical signals may be sent down a single wire (brake and taillights, for example). This is called variable voltage. If an ordinary diode is used in these applications, then the bulb will illuminate though the vehicle is braking whenever the taillights are on. That is, you can't tell the difference between the brake lights and running lights. Smart Diodes correctly modulate the voltage to activate only the intended circuit. The result is vehicle lighting that looks and functions as intended. Each vehicle requires two Smart Diodes. Vehicles with LED lights require a different kit than those with incandescent bulbs.