mini motor driven horn

how do i install amini motor driven horn to my car alarm with a relay

This question is pretty vague. What are you using to activate the relay that will be supplying the horn? Say you are using a negative aux output from an alarm, you could wire the relay like: 85 : Aux output from alarm 86 and 30 : +12V fused constant supply 87 : +12V output to horn If this is not what you are trying to achieve, take a look at this page it covers relays pretty well. If that still does not answer your question take a look at this page as it is an entire forum dedicated to relays and their applications.Installer, IT support, and FFL. I need less hobbies.