I bought a very nice 2001 Taurus family car, it's a creampuff--it looks and drives like new--I thought everything worked perfectly but we just got our first cold snap and I turned on the heater--fan goes, but we get no heat/defrost inside the cabin. The coolant is perfect, looks new,--I was looking for the heater core valve to be sure it was opening/closing but I don't see it under the hood. Anyone know where it is and how to get to it? There is no evidence of sludge anywhere in this coolant system. Anyone know how to check this heater valve and its operation? Thermostat works well, temp comes up fast but needle stays in the center of the guage. Thanks in advance.