Macbook A3241 No External Display

[Instafixx]

Using Schematics (820-03286)
Device was water damaged with USB C port not working.
Replaced that C port and it started working.

The other one which wasnt replaced (closer to the trackpad) isnt supporting external display via the USB hub. The one that is replaced - supports.
Replaced the working one too to enable display but didnt work.
Board is clean. One or two caps were green but nothing major.

Facing such an issue for the first time - which line or area should i be probing.

 

[2informaticos]

So you have external video from one USBC port?
Did you test USB activity on the other one?

Check if at least delivers 5V for external device.

 

[Instafixx]

Getting 20V on both ports.
Pen Drive detects on both ports.
But external video only on 1 Port

 

[2informaticos]

External video goes through thunderbolt protocol.
There should be your problem...

 

[Instafixx]

What should i check then ? Which lines? any help?