its on the throttle body
The idle control valve on a1999 Ford Expedition is on the upper part of the engine by the throttle body and fuel injection.
where is the heater control valve for a 1997 ford expedition
iac valve...idle air control valve
where is speed sensor location 98 ford expedition 4.6 engine nocruise control
Heat control is by air flow control doors in the a/c and heater box. There is no water valve.
Trouble code P0443 means:Evaporative emission control systempurge control valve circuit malfunction
the rear one is in the chassis
Ford Expedition & F150s have a common problem. Usually it will be a collapsed vacuum hose. Other thing could be your idle control valve.
It may be a bad Idle Air Control Valve .
The "Related Question" below is an extensive discussion on the 1999-2003 temperature control valve / heater control valve. It is likely the information will be similar to the 1997 / 1998 Windstar
IAC (Idel Air Control Valve)
where is the fuses for the factory amp in a 1998 ford expedition