If it's all corroded *again* and they keep dying maybe you need to consider moving the location of the relay to a drier spot. had the same problem with the OEM horns on the Suburban. They would work for a few months then one would get water in it and quit. Got tired of replacing them so finally remounted them up under the intake box behind the headlights instead of down behind the airdam. Just as loud, but drier....
Option B be would be to cut the ends off a ziploc bag, wire through the ends, pull the baggie over the relay and tape the ends tight around the wires. Also di-electric grease the connections.
