Front Display Interface Module (FDIM)
WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The FDIM contains a redundant rear window defrost button on the touchscreen display. The FDIM plugs directly into the APIM, and does not communicate directly on any network.