a thread like this went around a couple of weeks ago. I think I started it with the same question - how to disable the seat belt chime on a 2025 F-150, I've got the King Ranch.
Bad news the instructions in the manuals do not work on the 2025's. I just took it to the Ford dealer and had them use...
2025 F150 - Does anyone know how to disable the seat belt monitor ding, What's in the manual does not work, The red dash seat belt light never goes out, so you can not proceed to the next step of attaching the seat belt.