HVAC System - Automatic: Other Mercury Sable III

OFF Button

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

AUTO Button

Pressing the AUTO button will turn the EATC system on for fully automatic operation. The VFD will display AUTO and the selected temperature. The RCC 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 95°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.

VENT

Pressing VENT button will display VENT and the selected temperature in the display window. The system will operate with A/C compressor off, and air is directed to the panel vents.

Panel-Floor

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.

Floor-Defrost

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.

F-DEF

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

R-DEF

Pressing R-DEF button (defrost icon is also present) will activate rear window defogger.

BLEND DOOR ACTUATOR

The 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 Remote Climate Control (RCC) module. Internally, an electronic circuit accepts commands from RCC module and positions A/C temperature blend door using a reversible electric motor. An integral potentiometer feeds temperature blend door position information to RCC module.

Ambient Temperature Sensor

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

In-Car Temperature Sensor

Sensor contains a thermistor (temperature sensitive resistor), which measures temperature inside vehicle and inputs signal to RCC 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 RCC module. Sensor is located on upper right instrument panel.

BLOWER MOTOR CONTROLS

Note. DO NOT operate system with blower motor disconnected, or blower motor speed controller may be damaged.

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.

Blower Motor Speed Controller

Blower motor speed controller is located in the evaporator case, upstream of evaporator core. The controller converts low current signals from RCC module to a high current, variable ground feed to the blower motor. Blower motor speed is controlled by RCC module and blend door actuator position.

A delay function provides gradual increase or decrease in blower motor speeds. High-speed blower relay, integral with blower motor speed controller, gives maximum airflow in high blower position.

PRESSURE RELIEF VALVE

Pressure relief valve relieves high-side pressure build-up above 450 psi (31.6 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.

VACUUM ACTUATORS

Vacuum actuators control movement of air distribution doors. Two of the vacuum actuators are mounted on plenum. One vacuum actuator controls movement of the floor/panel door. A second vacuum actuator is used for panel/defrost door.

Another vacuum actuator, mounted on the fresh/recirculated air duct, controls movement of the fresh/recirculated air door.

In the 5-passenger seating configuration, an additional vacuum actuator is mounted on the heater plenum. This actuator controls airflow to the rear seat A/C register.

A/C Compressor Clutch

In any mode in which the A/C compressor clutch operates, the compressor clutch (signal) is controlled by Constant Control Relay Module (CCRM). CCRM is located in front of engine compartment, on upper radiator support. The Powertrain Control Module (PCM) will override the RCC module commands and disengage the compressor clutch during wide open throttle acceleration.

Clutch Cycling Pressure 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 ).

Check EATC °C To °F Display

With EATC system on AUTO, simultaneously press MAX A/C and F-DEF (front defrost) buttons for at least 3/4 of a second. If display shifts between °C and °F, system is operational. If display does not shift between °C and °F, Replace integrated control module. Retest system.

A/C SYSTEM PERFORMANCE

1. Park vehicle out of direct sunlight. Connect manifold gauge set. Start and run engine at 1500 RPM. Set A/C controls to MAX A/C and maximum cold temperature setting.
2. Set blower/fan on high speed. Close doors and windows. Insert thermometer in center vent. Operate system for 10 minutes to allow system to stabilize. Measure center vent output temperature. See «A/C SYSTEM PERFORMANCE SPECIFICATIONS»(ref-39943-S40353751982001011200000) table.
3. At about 68°F (20°C) ambient temperature, high side pressures should be approximately 100-200 psi (7.0-14.1 kg/cm 2 ). Low side pressures should be approximately 24-46 psi (1.7-3.2 kg/cm 2 ).
4. As low side pressure decreases, high side pressure should increase. When A/C clutch disengages, low side pressure will increase and high side pressure should decrease. See «A/C SYSTEM HIGH SIDE PRESSURE SPECIFICATIONS»(ref-39943-S34569251562001011200000) table.

A/C SYSTEM PERFORMANCE SPECIFICATIONS

A/C SYSTEM HIGH SIDE PRESSURE SPECIFICATIONS