2000 Town and Country with 3.3 engine. As soon as I turn the key on the radiator cooling fans come on, when I go ahead and start it the tach surges fro around 500 to 850 rpm. I keep getting a trouble code for low voltage at heat sensor and it is also hard to start first thing in the morning. I changed out the heat sensor and pigtail still getting same trouble code. Could the coolant fan motor relay be causing this problem ?? HELP !!!