Backlight issue

Hi, so my issue is that the left motherboard the one that has a Ribbon cable connecting to the main motherboard to the left motherboard so my problem is that, the right amount of voltage(3.7v) is going into the the main motherboard while the left one only is getting .76v and in order for the screen to turn on it has to have the same amount of voltage that is going through the main motherboard. So my question is does anyone have an idea or know what is the cause of this problem?

CHECK your socket/connector diode measure if any pin missing path to mainboard

I suspect it’s the BGA chip on the main board because that chip controls or regulates the voltage that goes into the lcd. Correct?

I would check the fpc connector and the ribbon cable. for my last 2 water damaged switch lites, the damages were there. Btw is the LCD working ? Can you check with a flash light on the screen?