Do you mean the ambient temp sensor for an automatic climate control system? And why are you concerned with it?
Ok now we have some more information. This is not the ambient temp sensor, this is the intake air temp sensor. If this sensor was defective enough to cause a running problem, it will usually flag a Check Engine Light Code, but not in all cases. Does your Dodge blow black smoke when it is cold? Does your Dodge use a lot of gas? Does the Check Engine Light come on while driving the van?
It could be few things causing this. It could be an idle controller not working properly, it could be a vacuum leak, it could be a dirty throttle body or a bad coolant temp sensor or other things. How does it idle when you turn on the A/C or when you are turning the steering wheel when your are parking cold and hot?
How well does your heater work? What I am getting at here is if your thermostat is stuck open, your car will run very rich and stall and eat gas when it is cold. You live in cold climate and this makes the situation even worse. Do both the upper and lower radiator hoses get hot when your van is warmed up?
Ok, your heater works fine. This is good. Do you know of a good mechanic( who is reasonable ) who can check your Coolant temp Sensor readings and your Intake Air temp sensor readings with a scanner. Have him/her check for any vacuum leaks as well. I am assuming that your van is in good tune-up shape with good plugs, wires, cap-rotor etc. Sometimes a shop will diagnose a problem and then you can replace the part(s). I do this for people with Emission Inspection Failures on occasion. By the way, usually both of these are located in the Intake Manifold. They are usually not very expensive parts. ( $20 or so )and can be purchased at a good parts store.
Look at the Oxygen Sensor when it is warming up. Is it reading high (.900+ ) or low (.100-200). Also, be sure to note how long it takes for the van to go into "Closed Loop". The fact that it is surging sounds like fuel management condition. ( too rich/too lean) Best of luck. I will be in the office on Friday if you have any more questions.
The Ambient temperature sensor and mounting bracket are secured with a screw to the upper radiator support, just to the driver side of the hood latch and behind the radiator grille Temperature Sensor Remove/Install Unplug the temperature sensor wire harness connector. Remove the screw that secures the temperature sensor and mounting bracket to the radiator support and remove the sensor. Reverse the removal procedures to install. The Ambient Temp Sensor is for the temperature reading on the overhead console