[SRGN]

Check if the horn relay clicks when the horn button is pushed for starters. If the relay clicks, chances are it's bad horns, but you would need to verify they were getting power before condemning them. As far as the dash lights, try rotating the dimmer on the headlight switch back and forth a few times, sometimes it's just a little corrosion in the switch that can be cleaned up. If it's not the dimmer, before checking anything else make sure the taillights work when you turn the lights on. The dash lights are powered by the tail circuit, so if the taillight fuse is blown, the dash lights go out at the same time. Report back with your findings.