* Under the hood in the fuse box: This is the more common location. The fuse box is typically located near the battery. Look inside the fuse box for a relay that's labeled "horn" or has a horn symbol.
* Behind the dashboard: Less common, but possible, especially on some later model years. Accessing this would require removing some interior panels. You'd need a wiring diagram for your specific year and model to pinpoint its exact location behind the dash.
To find it definitively:
1. Consult your owner's manual: This is the best place to start. It should have a diagram showing the location of all relays and fuses.
2. Use a wiring diagram: An online search for "[Your Dodge Neon Year] wiring diagram" should yield results. Look for the horn circuit to trace the relay's location.
3. Visual Inspection (Under the Hood): Carefully open the fuse box and examine each relay. If you're unsure, don't disconnect anything without knowing what it does.
Without knowing the specific year of your Dodge Neon, it's impossible to give a more precise location.