front camera doesn't function, rear okay?

I replaced the LCD, Digitizer(magnet dropped on top.),. The Cable for, power, volume, mute (found pinched and ripped in half [I blame the corner at/where the cable folds down and around the front camera, it's sharp I put elec-tape small piece] helps.

Okay. My Front Camera stopped working.? when I switch from rear Cam to front Cam? The rear Image freezes? The front Cam, wont even show anything? switch back to rear and Okay?...

I took it apart , Replace with a new Cam?, Did a Software update, Same result_,!.

Help help help, I'm stumped??. Maybe MB? Front Cam?

LJ.