An after market air horn relay is a device that is used to control the flow of electricity to an air horn. It is typically used when the air horn is not being used, in order to prevent the battery from draining. When the air horn is activated, the relay will close the circuit and allow electricity to flow to the horn, causing it to sound.
There are several benefits to using an after market air horn relay. First, it can help to extend the life of your battery by preventing it from being drained by the air horn. Second, it can help to improve the performance of your air horn by ensuring that it receives a consistent flow of electricity. Third, it can help to protect your air horn from damage by preventing it from being overloaded.