It's at the end of the spark plug wire. :laughing: All wires have 2 ends but it will be at the end you can see. The wire is black with rubber insulation, and about the size of a pencil. It often / usually has a 90° rubber thing at the spark plug end we call a boot.I feel like a complete idiot. I can not locate the spark plug on a John Deere 105. Can someone tell me where it is?