CHEVROLET LUMINA ENGINE COOLING

This Is My Daughter's Car, And I Am Helping Her Change Her Ect Sensor. That Was The Code It Threw When She Had It Checked. Where...

The Fans Work With The Air Cond. On, But Won't Operate Otherwise. Relay, Fuses Fine. Changed Temp. Sensor, Still Won't Come On....

Does The A/c Have To Be Charged For The Fan To Kick On When You Turn The A/c On?