A/c-Heater System - Automatic: Other Ford Expedition I

FUNCTION & OVERRIDE BUTTONS

Note. If function calls for compressor clutch to operate as part of the function, it will do so only if ambient temperature is above 50°F (10°C).

OFF Button

The OFF button will turn the EATC system off. The Vacuum Fluorescent Display (VFD) will be blank, unless the OUTSIDE TEMP function has been selected.

AUTOMATIC Button

Pressing the AUTOMATIC button will turn the EATC system on for fully automatic operation. The VFD will display AUTOMATIC and the selected temperature. The EATC module will maintain selected temperature by controlling compressor clutch operation, airflow direction, temperature blend door operation and blower speed.

TEMP Rocker Switch

Pressing the TEMP rocker switch once to the right will raise the selected temperature incrementally. If the rocker switch is pressed and held down, the selected temperature will be raised in one degree increments until switch is released or 85°F (29°C) is selected. If switch remains depressed after 85°F (29°C) is reached, the system will increase in a single step to maximum setting of 90°F (32°C). Pressing the rocker switch to the left will lower the temperature in a similar manner. Minimum selected temperature is 65°F (18°C).

OUTSIDE TEMP Button

Pressing OUTSIDE TEMP button will display ambient temperature on VFD. Temperature will remain displayed until OUTSIDE TEMP button or any other button is pressed.

FAN Rocker Switch

Pressing the FAN rocker switch to the right (+) will raise the blower to the desired speed. Pressing the rocker switch to the left (-) will lower the blower speed in a similar manner.

MAX A/C

Pressing MAX A/C button will display MAX A/C and the selected temperature in display window. Blower will operate at high speed and recirculation function will be activated. Air inlet door closes to outside air.

VENT

Pressing VENT button will display VENT and the selected temperature in the display window. The system will operate with air directed to the panel vents and will use outside air. Compressor clutch will be OFF.

PNL-FLR

Pressing panel-floor icon button will show panel and floor icon and the selected temperature in the display window. Air will be equally distributed between panel and floor vents.

FLOOR

Pressing floor icon button will display floor icon and the selected temperature in the display window. Most air will be directed to floor ducts, with a small amount going to the window demister and defrost vents. Compressor clutch will be turned off.

FLR-DEF

Pressing floor-defrost icon button will show floor-defrost icon and the selected temperature in the display window. Most air will be directed to floor and defrost vents, with a small amount of air going to side window demisters.

DEF

Pressing DEF button will show defrost icon and the selected temperature in the display window. Most air will be directed to defrost vents, with a small amount going to floor ducts and side window demisters.

Scheme 16

A/C ELECTRONIC BLEND DOOR ACTUATOR

The A/C electronic blend door actuator is located on rear of A/C evaporator housing assembly. It controls A/C temperature blend door movement on command from the EATC module. Internally, an electronic circuit accepts commands from EATC selection and positions A/C temperature blend door using a reversible electric motor. An integral potentiometer feeds temperature blend door position information to EATC module.

Ambient Temperature Sensor

Sensor contains a thermistor (temperature sensitive resistor), which measures outside air temperature and inputs signal to EATC module. Ambient air temperature sensor is located in front of condenser, on radiator support near center of vehicle.

In-Car Temperature Sensor

Sensor contains a thermistor (temperature sensitive resistor), which measures temperature inside vehicle and inputs signal to EATC module. In-car sensor is located on back of Integrated Control Panel (ICP).

Sunload Sensor

Sunload sensor contains a photovoltaic (sunlight sensitive) diode, which measures sunlight entering vehicle and inputs signal to EATC module. Sensor is located on upper right instrument panel.

PRESSURE RELIEF VALVE

Pressure relief valve relieves high-side pressure build-up above 420 psi (29.5 kg/cm 2 ), and prevents damage to A/C compressor and other system components. Pressure relief valve is located on side of high-pressure line, near compressor manifold.

Scheme 17

A/C CYCLING SWITCH

This pressure-sensitive switch, located on the accumulator-drier, controls the compressor clutch circuit based on evaporator core pressure. The switch controls evaporator core temperature to prevent evaporator icing. Switch opens when low side pressure is 22-28 psi (1.5-2.0 kg/cm 2 ). Switch closes when low side pressure rises to about 40-47 psi (2.8-3.3 kg/cm 2 ).

A/C SYSTEM PERFORMANCE

1. Park vehicle in shade. Place a fan in front of condenser. Connect manifold gauge set. Start and run engine at 1200 RPM. Set A/C controls to MAX A/C position and temperature control at full cold.
2. Set blower/fan on high speed, and close doors and windows. Insert thermometer in center vent. Operate system for 10-15 minutes to allow system to stabilize. Measure temperature at center vent.
3. Temperature must be 33-47°F (0.6-8°C) at center vent, with high side and low side pressures within specification. See «A/C SYSTEM HIGH SIDE PRESSURE SPECIFICATIONS»(ref-238-S35001983062000030800000) table. Low side pressure remains constant at 25-45 psi (1.8-3.2 kg/cm 2 ) throughout normal operating range.

A/C SYSTEM HIGH SIDE PRESSURE SPECIFICATIONS