This is for the 2018 Ford Fiesta with Sync 3? Looks like this, the screen is separate from the Sync APIM.
The LDVS cable will be longer than the version with the screen and APIM together. Like this:
1.5M 5ft FAKRA HSD Sync3 LVDS Video Harness Cable SYNC 3 System Upgrade Touchscreen to APIM Cable for Ford MyFord Touch or Lincoln Head Unit Stereo : Amazon.sg: Electronics
According to our screen database, the Fiesta screen is part G1BT-18B955-TD.
2018 Ford Fiesta G1BT18B955TD 6.5" Standard Flat
2013- 2018 Ford Fiesta OEM 6.5" Touch Screen Display Monitor USED G1BT-18B955-TD | eBay
This could be bad connections on the video or power connectors, etc., also. Especially grounding. I searched around and found a similar issue with Explorers, etc.
FORD TSB #SSM 49245
Some 2020 Explorer/Aviator vehicles built on or before 30-Sep-2020 may experience an intermittent or constant blank/black screen on the center infotainment display due the low voltage differential signaling (LVDS) cable at the SYNC accessory protocol interface module (APIM) not being fully seated. Verify that the connector is fully seated into the APIM prior to performing any other diagnostics or repairs on the vehicle for this concern. If the connection is found loose, re-seat the connection and retest.