OK, after reading the refrigerant pressure from the climate control codes, even after reaching pressure at 14 bar (low speed should kick in) and up to 17 bar (high speed should kick in), auxiliary fans still did not come on. The auxiliary fan did come on at low speed after eventually reaching the 95 C engine temperature. So, it looks like the problem is not on the engine temperature switch, but on the refrigerant pressure switch.

I tried jumpering the pressure sensor connector (has 3 wires) on the side of the air drier, but the auxiliary fans still would not come on. Does anyone know, which wires to jump and should the connector be back on the pressure sensor?

I'm really thinking that it is the pressure sensor because I've already checked the relay(green) and fuses and they are all okay, but I want to confirm this before purging the system out and the refilling.