[Will N]

I can see how this might work, depending on how the relay is wired, when the engine is off or the car is idling. When the engine is running at a speed where the generator is charging, the horn is wired right to the generator cutout and you have plenty of voltage to run the horn. If the wiring of this relay bypasses the generator cutout, terminal box, ammeter and starter switch terminal (which is the path the hot wire for the horn takes to the battery) and goes directly to the battery, with fewer possibly corroded connections that can cause voltage drops, it can be more reliable. But IMHO, this relay is just a band-aid. Bright and tight fellas! Clean those wire connections 'til they are shinning and snug them down, Clean the battery terminals and make sure you have a good ground and your horn will work as intended without adding yet another component that can go wrong.