I installed a new dash wire harness and new engine wire harness but my horn isn't working. The horn and relay are original. The car is a 70 Roadrunner. The horn worked when tested when I first got the car running a few months ago. The horn does nothing now. The horn relay clicks when the horn button is pushed but still nothing from the horn. I ran a wire from the battery directly to horn and still nothing. Is the horn no good, the relay no good or both?

Make sure the horn has good ground.
If it still not honking,replace it.
Relay is getting power when you here it click.

Tim

Just because the relay clicks does not mean it is sending anything to the horn. Put a meter, or at least a test light, on it and see if there is anything coming out of the relay. If so, see if there is anything at the horn.

Or throw money at it.

Tim

Test light on the wire at the horn lit up when horn button was pressed. I guess I got confused by the fact that the horn worked when tested initially. Looks like the horn is bad now. Also explains why it won't honk when directly hooked to the battery. New horn ordered, hopefully problem solved. Thanks for the replies and advise.

I need new glasses

there is a small "trimmer" screw on the horn body, turn it a C hair CW & CW then back to your starting point & jump fire to the horn again & see if it sounds (I'm assuming it is grounded). Do ya feel lucky?