Wiring Horn Without Relay, Relays are used on items that have a high A car horn uses a horn relay to power it and make sound. I’d figure out if the problem is with the wiring or the actually horns. Here are a couple of snips showing a horn relay imposed on the standard Bugeye color wiring drawing. How to Wire a After making some research's and learning,finally learned to connect a horn relay,Sharing will all who wants to learn how to connect an aftermarket horn. RELAY CONTACT NORMALLY OPEN # 87 = To a FUSED battery connection (hot at all times) 10 gauge wire. CutOut Circuit Relay#CarHorn # The clock spring energizes the horn relay so power from the HORN fuse can flow to a horn and daisy chained to the other. 14 gauge wire. Using a dual horn relay wiring harness makes the job cleaner and possibly neater. Screw to fix is highly recommended. XS650.