Thunderbolt Display issues after replacing Thunderbolt/Magsafe Cable

Hello -

I need assistance. I replaced my Thunderbolt Display Thunderbolt and Magsafe Cable following these directions... Apple Thunderbolt Display Thunderbolt & MagSafe Cable Replacement It was very easy even with my inexperience. Really, the hardest part was trying to keep the screen clean when putting it back on (it’s still streaky but not facing a window, so whatever, hahaha).

But now when I connect the Thunderbolt Cable, the screen flickers and moves around like crazy and goes black randomly. The other parts of the cord and display work as expected, the USB ports connect, the camera and sound work, and the Magsafe is charging my laptop.

I know I didn't damage the logic board as when I plug in a stand alone Thunderbolt Cable to the port on the back of the display to my laptop the screen works fine, I just don't get the camera, sound, and USB ports. I tried restarting my laptop, resetting SMC, and resetting PRAM.

Does anyone have any advice? My cousin thinks maybe the cable wasn't pushed in all the way on the back of the logic board, but would the camera, sound, and USB still work if that was the case? Or maybe I just have a faulty replacement cable? Could the Thunderbolt port on the logic board be bad? What should I check next?

Thank you,

Lindsay