I.on [美 ɑn, ɔn, 英 ɒn]介词on often appears as the second element of certain verb structures in English (count on, lay on, sign on, etc). For translations, see the relevant verb entry (count, lay, sign, etc).
These include possibly loose seat mounting bolts that could rattle on rough road surfaces and a "request for information" on the rear seat belt buckles.