My horns didnt work also. What I did was spray WD-40 in the horns and soak them. Let them soak for about a week, then poured out any left over WD-40 and dried the horns. They work great to this day. I did bench test them before putting them back in the car.
If you do a search you should find the same thread I used, dont remember which member told me to do this though.