Chrysler Repair: 05 town and country: engine running too cool

Question
QUESTION: as the engine is at idle it slowly gets to 1/4 on the temp gauge the heater will get warm the electric fan will turn on as it climbs a little over the 1/4 mark on the temp gauge. As you drive the temp will decrease down to the cold mark on the temp gauge, have checked the thermostat and it is closing, have recently changed the (ETC) Engine Temperature (Control?) sensor the check engine light was on autozone diagnosed it, replaced light went off. It will not get to a running temperature and am not getting anywhere with the the local auto part store it is cold where am at and am wondering why it is not getting to running temperature, and why the fans are turning on so early. was wondering if you had any ideas or any source I should go to to investigate to solving my temperature issue. I thank you for any ideas and leads that you could give me a shade tree wrench! LOL

ANSWER: Hi Chadhenry,
Do you recall what the fault code was that Autozone found? If it was related to the engine temp sensor, and as the result you replaced the sensor, it still may be the case that the issue is with the wiring of the sensor to the powertrain control module. Let me know which size (L) engine that you have and the code number if you know it.
Do you have a volt-ohm meter? I can tell you how to verify the wiring of the coolant temp sensor. It could be shorted/open and thus causing a false reading. Also, how does the temp of the radiator top hose feel in terms of its temp, and do you still get good heat in the cabin or does it drop as is shown on the gauge? The gauge may be inaccurate if the temps seem to be normal.
Another possibility is that the thermostat setting may be too low (opens too cool) even though it is closing. You can put in new thermostat with a higher set point. You could remove the thermostat and put it in a pot of water on the stove and measure the water temp when the gauge begins to open and compare that to the number on the thermostat itself. It should begin to open at about 188 or so.
Please read the PS below and respond to it.
Thanks,
Roland


---------- FOLLOW-UP ----------

QUESTION: yes, I have put the thermostat in hot water on top of stove it is opening at about 150 degree and is fully opened at 210 degree. the code I didn't keep for after the (ETC) was replaced the check engine light went off. got it inspected they had said that it was running fine so threw it away. I do have a volt-ohm meter, the heat in the cab does decrease when the temp gauge decreases the two hoses from the heater core feels the same, I have recently blown the heater core out with air before I replaced the (ETC) after replacing (ETC) disconnected the battery to let system reset. the engine size is a 3.8lL touring model

Answer
Hi Chadhenry,
I believe that your thermostat is opening at too low a temperature (150) and so you should replace it. Get one that is nominally in the range of 190-195 and I would expect that the gauge reading and the actual operating temperature of your system will improve considerably.
Roland