Hardware Joy-Cons will only sync to the console if I pair them through the Sync button

[Gabriel2Silva]

Connecting both Joy-Cons physically to the Switch Joy-Con rails will display a "Paired" message once, but the Joy-Cons won't work wirelessly afterwards if I remove them from the rails. Only way of making them work wirelessly is to manually sync them through the Sync button on the Controllers option. Any idea why this happens?

 

[de9ed]

Make sure the white and black cable ( wifi and bluetooth) sits tightly on the pcb IF you have opened it up recently

 

[TpmKranz]

@Gabriel2Silva were you able to solve your problem? I'm currently facing the same issue with my right Joy-Con. Did yours also give up connecting after one cycle of the LEDs? Mine only tries to connect for an appropriate amount of time (cyling through the LEDs multiple times) if I long-press the sync button, but that will, of course, only sync if I'm already in the controller pairing screen. Waking the Switch up remotely is impossible this way.