My 04 GT is having some overheating issues. I have come down to the fact that its my cooling fans. They do not turn on. I have replaced Thermostat, Radiotor flush, and new Temp. sensor. Ive noticed today that my cooling fans are not turning on at all. When I turn the A/C on both fans turn on. When car is idling, and in traffic it overheats fast. When on highway car temp is fine. What to do? Help!