There's lots of threads out there talking about the electric/heated thermostat on the 01-03 rangers. However I haven't seen any on how the heated thermostat works.

Why did Ford use this design? Compared to normal mechanical thermostats, is it more likely to fail stuck closed instead of open? Is there a motor that controls its opening and closing? And why is it called a "heated" thermostat? Why would you want to add any heat to the hot coolant?

 

Thermostat has a heating element inside the housing, that's the electric part, the thermostat is just a regular 180degF model but part of the housing

These 2.3l Duratec engines are a Mazda L engine designed to be transverse mounted(sideways) in FWD cars
Ford thought there would be overheating issues if the lower radiator hose thermostat setup didn't open quick enough when upper engine reached 185-195degF, when used in Rangers longitudinal RWD setup
So they added a heater to be sure it would open

But there was no need for it, so Ford dropped it in 2004 and up models, also dropped the IMRC

People do just put in the much cheaper non-heated thermostats with no cooling issues in the 2001-2003 2.3l Rangers and Mazda B2300s
But the CEL(check engine light) will come on because heater is disconnected, you can add a resistor between the 2 wires which is what a heater is, lol, or some just leave the old one connected and tuck it up out of the way

No, I don't know what resistor they use, but you can Google it, I have seen posts about it

 

Can use a MultiMeter\OhmMeter to measure resistance of the TStat's Resistor\Heater element.
If replacing it with a different resistor, go with next higher standard Ohm resistance,
then make sure new resistor is watt rated for the current+power that it will draw running at 12~15vDC.
Ohm's Law for DC: Volts^2/Ohms = NominalWatts; conservatively get a Resistor rated >150% of this calculated watt value.