Carefully release the two Wi-Fi antenna cables from the Wi-Fi card

Bring the two cables out to the same side as the LCD screen. In other words untangle them from the hinge

Check if they are broken. There are two ways

Fingersnap the loose end of the cable to see if it flexes abnormally in a specific point, indicating a broken cable. In the video you can notice a specific point just at the axel where the cable flex much more than the rest of the cable

Connect an ohm-meter in the mini PCI-E end between the shield and the core. Start wiggle the cable

The resistance should always be zero, because of the antenna layout (An open-ended rectangle)

If the cable is trashy, the resistance will deviate from zero when the cable is being wiggled