cooling fan not coming on

Maybe you replaced the wrong coolant temp sensor or got a bad one. The ECT is on the passenger's side front of the motor on the heater tube - also make sure you bled the air out of the heater tube so coolant is in contact with it. The other temp sensor is in the intake with one wire going to it - it's for the gauge. If the fan comes on only with the AC on that is THE classic diagnosis of a bad ECT. I always use Ford ECT because I have gotten bad ones from parts stores.

I have a tech article on my site - see sig that covers cooling system problems and diagnosis.

Don