My fan is bely driven not electric why am i getting Po480

Question

2006 trailblazer 4.2 liter engine
Have changed thermo-stat  changed oil twice
flushed radiator and cleaned throttle body
and power washed radiator externally

Answer 1

P0480 Cooling fan relay 1 control circuit

When this code occurs the cooling fan is set to 100 percent, meaning it is commanded to stay on , if the cooling fan is on, then the problem is with the cooling fan circuit for the cooling fan.