OVERHEATING

MY 98 P71 CROWN VIC HAS BEEN OVERHEATING. AIR CONDITIONER SUDDENLY WENT WARM AND TEMP GAUGE WAS IN THE RED.
TURNED IT OFF FOR A FEW MINUTES TO LET IT COOL DOWN. 15 MINUTES LATER, RESTARTED IT AND WAS NO BETTER. THE RADIATOR FAN WAS NOT RUNNING. CHECKED IT AGAIN 2 HOURS LATER AND FAN STARTED RIGHT UP AND WAS GOOD FOR ABOUT 20 MINUTES AND IT DID THE SAME THING. REPLACED COOLANT TEMP SENSOR- SAME THING. REPLACED FAN MOTOR-SAME THING. THEN, I REPLACED WHAT I PROBABLY SHOULD HAVE REPLACED FIRST, THE RADIATOR FAN RELAY. STILL SAME THING.AFTER THE MOTOR COOLS COMPLETELY DOWN, FAN RUNS FINE FOR 20-30 MINS THEN STOPS. NOW WHAT? WHAT ELSE CONTROLS FAN?
STEVE

I think there is a temp sensor for the fan.If so I would replace thatThe fan will only run when it is between 190* and 220 degrees.I would also replace the thermostat.