Joycon R lost wireless functionality

Hi, I recently replaced the joystick in my joycon (r) which I have done 5 times before. After I replaced it the joycon stopped working.

When I slide the joycon into the switch the animation plays showing it is connected to the switch, the buttons and control stick work while connected but the player led never lights while disconnected and it doesn't connect wirelessly.

I checked the battery with a multimeter and it is working fine(showed 4.1v when the casing says 3.7) . I've checked every ribbon cable connection. I have connected a different 3.7v battery I have to the joycon and it did not power up.

What can I test/fix to work through this problem?

Edit: this is definitely power source related since trying to update the controller the system serves me a this joycon has too low battery to update message. Is there a way of testing where on the power reciever the problem is?