I can't find any diagram or YouTube post that shows where I will find the heater hose control valve that diverts coolant inside to the heater core to warm the cab. I have perfect a/c temp, blower motor works on all speeds, all air directions correspond to the correct setting on the dial (i.e. panel, floor, def, recir), and blend door actuator functions because when I have the fan blowing, and adjust from full hot to full cold, I can hear the motor & gears and feel the air output change it's density (corresponding to a plastic flap moving to one side as it switches the source of the air) - only thing is the air does not get hot, or even warm. In fact it seems like it's the same temp as the super cold a/c output air. So it's gotta be the heater control valve stuck closed, doesn't it? Or seriously in need of a core flush. I need some reliable diagrams. Haynes manual doesn't touch this particular subject.
What makes this problem better or worse?
Never works no matter what direction, setting/temp I have it set at
How long has your 1998 Ford Expedition had this problem?
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Hello, yes, a heater control valve can be a concern - but - so can your temperature blend door motor.
I do not have a schematic to refer to, but I believe it is located at the heater hoses that enter the heater core. Check there.
