OLD SUB, This adaptor is sealed but ill venture to say that it has 3 to 5 diodes inside.
The device is used for exactly this application and works well for it. The differance is that it is used on oh lets say a toyota truck with turn signals and stop lamps that are on seperate bulbs. You hook it to the truck wiring before your trailer wiring and it allows the trailer to have both stop and turn signals on the same bulb.
Its really pretty cool.
Polarcat, I do have a 12 v system.
