Radiator fans only come on with red light

[alec801]

I've got a 2006 yaris.
Would anybody have any ideas as to why my radiator fans won't turn on until the red overheating light comes on?

I can see the temp go up to 80-90°C where the fans used to turn on but they won't come on anymore.

I have replaced thermostat, coolant temp sensor, fan relay 02, checked a few related fuses but figure out what is going on.

any ideas?

[06YarisRS]

Water pump? Breaks in wiring/grounds? All connectors are seated properly? The fan itself? Maybe try applying a direct 12v to the fan and seee if it works.