Left joy con dead, tried new rail and new joycon. system fan is working

I’ve replaced a damaged USB C port and USB charging chip ( at the back of pcb) and got the switch working, but the left joycon will not connect or charge. Ive seen others noticing the fan also not working and it being a diode problem but the fan is working fine.
I’ve tried a replacement rail and replacement joy con with no luck.

have you checked the components around battery connector next to the left side rail cable socket

I’ve only checked the caps for shorts. Not sure how or what else to test for tbh

Have you cleaned the connector for the joycon flex cable on the pcb?
You need to make sure that it is clean from the inside, cleaning spray works really good

I had some flux in mine and the left rail didn’t work at all