[Axle]

If it continues to blow with only the wire, then that wire is grounding somewhere. Maybe the spring is bending enough to make contact with either the lock plate or adaptor. Take a plastic staw, drop it into the hole and bottom it out, mark straw at the top, measure down to where the nub of the horn wire locks in, cut straw shorter by that amount. stuff in hole, insert horn wire and see if your cured.