Fan RPM detection issue

You are convoluting a capacitance value, and a capacitor component code. a cap marked "104" is a 0.1uf cap.

When we get past that, it seems that there are still a lot of unanswered questions... for example, it's really confusing around "T3". If you are going to create non-standard components, please at least use them consistently.

Why not just scrap the diagram and start from scratch? There will be too much back and forth trying to understand it this way. Clearly label all the parts.

You could have drawn a simple line from pin 2 to the PWM pin, by going to the left of the Processor block. You didn't have to use a dotted line. That kind of thing just confuses someone who reads schematics a lot.