First Startup, Joy-Con Chargin but not connecting

[TiJoao]

I bougth a second hand nintendo switch with a (supposedly) faulty controler uppon closer inspection the problem looked to be with the nintendo itself. The joycon rail had its cable ripped off.
But even tho i changed the rail to a new one the controller charges but does not connect (the blue on) making me stuck in the startup.
Cab anyone help my ty.

Couldnt upload images so i made a link if it helps ttps://photos.app.goo.gl/JtQwqF3nsND9NcH89
TiJoao

[Calvin]

Maybe this could help:

The values are mV in diode mode. (No powersupply, no battery, red probe on ground and with the black probe on the pins/pads)

[Integ209]

In my case it was a water damage switch. I had to replace the connector. Not sure if it’s same issue

I Heated from the bottom of board up