John Deere Ignition Module & Key AM120105 AM131841John Deere Ignition Module & Key. AM120105 – Ignition Module – 1. AM131841 – Key – 1. GT242 – Serial #s above A027344 B025017 C025190 D035000. GT262 – Serial #s above A045000 B045000 X029204. GT275 – Serial #s above B045000 C045000 D045000. LX172 – Serial #s above.