I have asked for advise on wiring and the majority of the experienced people have suggested that when in doubt use a relay especially with air horns and lighting. Air horns and lighting tend to tax the electrical system and require more current. The following are schematics that I have acquired from different people. I drew redrew the schematics wired to Auxiliary Fuse Blocks.
This schematic was submitted by Dick McCulley from Tulsa, Ok