Fan0 is parts cooling 4010,
Fan1 is Tool,
Fan2 is parts cooling 5015.

All physical fans work when plugged into always on

I have measured Fan0 output with multimeter and shows 24+v when fan @0% and 20v+- when fan@any other value.

I will test based on the recommended links

Config is attached to OP

Fan0 and Fan2 are configured to be parts cooling and not Thermostatically controlled.

FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.1.1 ELECTRONICS: Duet WiFi 1.02 or later FIRMWARE_DATE: 2020-05-19b2
config.bak.g

All fan entries are default from the RRF Configurator

Fans 1 & 2 work as expected but fan 0 does not work at all

Fan VIN jumper set to VIN, Mosfets look ok