2002 Taurus Low/High speed coolant fan failure

No low/high speed electric coolant fans.

Symptoms -
Boil over, lost coolant, and a False indication on temp gauge, because of lost coolant or contaminated ECT sensor.

Notes -
HVAC High max cool, both coolant fans work.
Disconnect ECT sensor, and both coolant fans work. (Open loop)

No Low Speed coolant fan , it's suppose to turn on @ 216F & off @ 212F
No High Speed coolant fan, it's suppose to turn on @ 228F & off @ 222F


Found a bad coolant fan connector/resistor on electric coolant fans.

You either left out some details, or you may want to be careful to ensure this car is really fixed. What "trouble" were you having with the radiator cooling fans?

The ECT sender for the gauge is NOT the same as the ECT sensor used by the PCM to activate the fans. So the reading on the gauge may not be representative of when the fans get their trigger to run.

Also since both fans ran when you turned on the A/C or disconnected the ECT sensor, a bad connector would have still been in the circuit for that operation.

-Rod

Both ECT sensor/sender sensors for gauge & PCM were getting bad signals, because sensors don't work good during boil over or steam.

During the summer months the HVAC was on high max cool, thus the coolant fans were doing there job..

Everything was good until fall, the HVAC was off and there was No Low/High speed coolant fan operation to keep her cool.

Suspected -
Fan fuse, Fan relay, ECT sender, or coolant resistor plug.
Found a bad coolant resistor plug, it's almost sort of like a HVAC blower resistor, see AF www.automotiveforums.com/vbulletin/showthread.php?t=1080408 (http://www.automotiveforums.com/vbulletin/showthread.php?t=1080408)