The horn stopped working in our 2024 Elantra. This is a widespread issue (see NHTSA complaints and Reddit posts). I called ahead to verify with the San Leandro dealership that parts were in stock to perform this repair under warranty (prior to scheduling appointment). We arrived and were told that parts were actually not available (after a 3-hour diagnostic). What changed? Hyundai issued a TSB (technical service bulletin) informing dealerships of how this issue is to be repaired (designating a specific part number, while excluding otherwise qualified Hyundai parts). Without TSB, the dealership could have performed this repair under warranty with the in-stock parts. The dealership could still perform the repair, but Hyundai would not reimburse them under warranty. With a[XXX] wife, I was unable to wait and return later for the warranty to cover the repair. I paid $429 to the dealership for the repair to be done with in-stock parts. I left the dealership with a genuine & working Hyundai horn, but it was not covered by Hyundai’s warranty. Hyundai has refused to reimburse us. Two key takeaways: 1 — Hyundai is denying there is a widespread issue while secretly telling dealerships how to address it. The unpublished TSB demonstrates that Hyundai is aware of a widespread safety issue, and is failing to issue a recall. The majority of NHSTA complaints for this vehicle reference horn failure. This is a safety issue. I was involved in an accident where I could not warn another driver before the collision. 2 — The TSB is a mechanism by which Hyundai is refusing to perform repairs that should be covered by warranty. This is a violation of Hyundai’s stated commitment to customers that is not stated even in the fine print of the warranty. [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)