As Kevin says, there was no relay used on that diagram. We do not recognize the part you show. So probably someone has added this part. So now you need to show us good pictures of that part, all it's markings, it's part number and where wires go. Also need to show the horn(s) and how many wires are to them. Then we will tell you the answer to your specific case. Need many good clear, well lighted pictures with explanations of wiring.
