Macbook Air: diagnosing bad I/O board

I have an 11 inch macbook air (I think 2014..) I had to replace the keyboard a while ago, the replacement worked fine for a bit but then keys near the power button stopped working. I took it apart, replaced the fan, cleaned it up and checked for issues, put it back together and now the computer wont turn on/won't charge. It worked for a day and then stopped. Now the power cord does not light up with the orange/green lights when plugged in.

I have tried two power cords so that's not the issue. I've disassembled and reassembled the macbook several times to make sure everything is plugged in correctly.

Issues I noticed which I don't think would cause this:

1. One of the connections to the wireless WIFI bluetooth card is snapped off.

2. plastic on the logic board which holds the cord from the fan in place is slightly broken.

I'm wondering:

1. is this an issue with the I/O board? or possibly bad logic board?

2. how can i troubleshoot with the I/O board to see if it's okay?

3. what is required for the orange/green light on the charger to turn on when plugged into the I/O board? Can the I/O board be disconnected from everything (mic/fan/logic board) and the charger will still light up when plugged in if the I/O board is functional?

Thanks!