Ok, hooked test light to each of the plugs and had my son press the horn button, each horn press resulted in the test light illuminating. So it appears power is getting to the plugs, so must be grounding or the horns are bad?

The horn brackets are powder coated so perhaps I should lightly sand the contact area with the horns and also where it contacts the rad support?
But as I stated i ran a power wire to each horn and nada?