Try your fan switch(like the others suggested). Your tstat is seperate from the housing, just pop it out...also its not the reason the cooling fan is not coming on. Make sure you bleed the cooling system once you put it back together or else it will overheat constantly. Cooling fan coming on with the condensor fan when the a/c is on is normal on honda's.

Just curious, how are you sure its the radiator cooling fan?