7. Moving onto the electronic air solenoid, this special air fitting was installed and was the connection point for the air hose from the solenoid to the horns. The large 1/2-inch air hose went into one side of the solenoid and then exited into the four 5⁄16-inch air hoses. It's ideal to mount the solenoid as close to the horns as possible and keep the air hose that runs to the horns as short as possible. This will provide instant and crisp horn blasts.