Question on passenger stop light circuit

Hi, I was checking my car on the weekend and noticed the passenger light does not work when the brake pedal is pressed.

The turn lights work on both sides

When I activate the hazzard lights only the driver side works.

I read some threads about this kind of issues and removed the kick panel and checked there, when the brake is oressed only one wire has 12v, meaning the connector does not have an issue, the problem seems to be upstream in the wiring

The brake switch is new, and does work because the driver stop light works fine when the pedal is pressed.

It seems the only thing I have left to check is the turn signal switch, how is that one checked?, does anyone has pictures on how it should look like and what wires should have voltage when the brake pedal is pressed?, how is the switch removed?. I read it needs to be centered, but centered in relationship to what?.

In case the validation turns that there is an issue with the switch, what is a reliable source to get a new one?. I read many people who gets new ones turn out to have defective new switches.

Thanks in advance for the info