My 2007 Mazda 6 horn does not work. What I've checked:
-Fuse is OK
-Relay does click when the horn button is pressed. I also swapped the relay with another one, with no benefit.
-Connected new horn, still doesn't work.

So... any idea what my next step should be? Thank you.

 

could be a bad negative from the the horn, run a wire from the negative on the horn to the negative on the battery, then press the horn and see if that makes a difference.

 

Thank you for that. Where exactly is the negative on the horn - I assume it's just the mounting bolt/attachment of the horn assembly?

 

yes, check around that area, it could be corrosion.

 

After check the power lead and the ground continuity as suggested earlier.
Using a volt/ohm meter have an assistant push the horn. As you have said you can hear the rely so that circuit is getting power and the steering wheel is not the problem. By passing the horn you should read voltage from the horn wire. If not the problem is between the relay and the horn. There is nothing else that wire runs so you can either trace the wire in the harness for damage or simply run a new wire from the horn rely to the horn.

 

Thanks for the info.

Turns out it was the horn. I replaced the horn and now it works. I think when I tested the new horn previously (uninstalled) I didn’t ground the horn bracket. All good now.

 

glad you have it sorted.

 

Thanks for returning and letting us know you solved the problem