Is the "Low Coolant" light on? It's on the left end of the dash, to the left of the Temp/Fuel gauges.
It's yellow and looks like a little radiator - and there are SEVERAL things that will make the light come on. Think of it as a "General Cooling System Alarm Light".

Read my post in the other thread (you know the one, the one you posted in earlier today).

If the light IS ON, then the ECM and FCM are not talking to one another - and that will be somewhat easy to fix.
If the light is NOT ON, then it sucks to be you - JUST KIDDING - but if it is NOT on, then one of three things is going on:

• The ECM is off in la-la-land. It is not sending pulses to the FCM so the FCM is running in emergency mode like it is designed to when it does not hear from the ECM every so many fractions of a second. Try shutting off the engine, disconnecting the battery cable - and leaving it off for five minutes. Reconnect and see if the ECM gets it's brains back in order like with the guy in the other thread.
• The ECM has good reason to run the fan at high speed and is doing so, intentionally. The challenge is to find out what that reason is. I will try to help all I can but with your temp needle working, not sure where to go with this.
• Your ECM is bad. I have a very hard time believing this one.