[pbfoot]

I have a 2005 Focus ZX4 S, the fan blower does not work in speeds 1 or 2 but work perfect in speeds 3 & 4.

Seems like the most common solution for a problem like this was to replace the resistor, (I tried that & nothing changed). In hindsight I should of did more diagnosis as it sounds like the resistor usually affect speeds 1, 2 & 3.

I am next going to try a new Fan Blower Switch.

Can anyone @FocusKnot describe how to remove the HVAC control cover to get at the switch? Or perhaps a video link. I'm think you probably just carefully pry the cover from the corners, but it's nice to hear it from someone who's already done this before.

Thanks in advance.

Yep. Use a plastic trim tool and it pries right out.