One of the wires on the relay is not used. I still have not found a 4 wire yet. I have a wire diagram for the relay. One wire goes directly to the battery, one wire to the fuse block, one wire to the ground, and the last wire to the switch(or switch leg. The switch will activate the relay, the relay closes witch will power the fuse block. with the fuse block now powered up, you can operate your switches. Let me know if this is the way you want to go. I will try to scan the wire diagram for you. If it can not be scanned, I will tell you what wire does what.