This may be common knowledge but...If you want to keep your original horns and they don't work it is simple to repair them. Drill out the rivets holding the two halves together. You'll find a metal plate sandwiched between the halves. Under the plate is a set of points and inside the same lower half an electromagnet. Clean all the rust off of the plate and horn body halves. Clean the points with emery cloth. Then put it back together. I used RTV sealer to seal the halves and pop rivets to hold them together. The horns now work.
Tim
Tim