cooling problems

i have a 95 mustang 5.0 with a W4HO pcm & aode. the fans will not come on at operating temperature.ok,this is what i have done so far.applied 12v to the #14 wire and the low speed comes on.i then applied ground to the #17 of the ccrm and the high speed runs.i can turn the a/c on and the high speed works.i then replaced the ect sensor and checked the voltage at the return wire and it is showing like 0.46 volts going back to the computer at operating temp.according to what i have read at a little less than 1/2 volt the low should be on. the pcm for some reason is not giving 12 volts to #14 to turn the low speed on.has anyone ran into this before.i am thinking pcm. is there a way to check it first..i am also getting a code 564 (fan control circuit failure)...thanks in advance

thanks hissin for the reply, this setup is actually in a 78 f100. i used the telorvek panel and wiring from the detail zone for the installation.the 4.6v i was getting was on the wrong side of the sensor.yesterday i put it on the other side and at 5.2v the low speed came on.the guy at the detail zone said that replacement sensors sometimes vary 5 to 10%. i have found that it just wasnt getting hot enough to turn the fans on.factory guage doesnt read numbers just c normal h.i used the truck radiator and it pretty big.i did some research on the ect & act sensors and there voltage and ohms runs the same according to a chart on ffi. on the truck when the ect is at 5.2v the act is 1.72v .is this to high on the act? the trucks seems to be running rich and not getting the mileage it used to.