I have a 99 expedition (5.4 V8)with front and rear heat. The hoses going through the firewall and to the rear are both cold to the touch when the car is warmed up. I am hoping the problem is my heater control valve that allows coolant to flow through the heater cores. All the auto stores sell one but I can't find it any where in the engine compartment unless it is between the engine and fire wall. Can any one send me in the right direction and tell me whee to find the valve.