Nintendo switch Joycons not charging fan not working, fan replaced still not working?

No obvious burn marks on the board, bought parts off amazon. Replaced fan as I hear joycon charging is linked to the fan. The controllers will connect when charged and slid into the rails and do make the switch click but they wont charge. Game system shuts down due to overheating when in game so it must be the fan.
How can I check the fan with a multi meter? It might be another dead fan, I also bought a screen off amazon and they literally just sent me a smashed frigging screen so I wouldn’t be surprised that I just got another broken fan.
Are there any fuses I can check etc?

did some reading on this forum,The diode by the fan connector what reading should I get ? The ic on the back of the board what reading should I get/ how do i check it?

It will 90% be the PU chip on thw back of the board.

It happened to be the diode actually. I was testing the diode and readings were jumping all over the place on diode mode.

The diode actually popped off when I was testing and now the console works great and controllers charge