A/c-Heater System - Automatic Ford Taurus I

A/C SYSTEM SPECIFICATIONS

A/C SYSTEM SPECIFICATIONS

DESCRIPTION

The Electronic Automatic Temperature Control (EATC) system automatically maintains selected in-vehicle temperature. The control panel uses a microcomputer to analyze temperature/blower speed selection, passenger compartment temperature, ambient temperature, engine temperature, sunload sensor, and cold engine lock-out switch inputs.

The microcomputer determines the correct conditions for A/C compressor clutch engagement, blower speed, blend door position, floor-panel door position, panel-defrost door position, and fresh-recirculated air door position.

A small electric motor is used to operate temperature blend door. Vacuum actuators are used to control remaining air distribution doors. A feedback circuit is used with blend door actuator to enable the computer to identify the door's position.

Blower motor is controlled through the Blower Speed Controller (BSC). The BSC is required to convert a low voltage signal from control assembly to a high voltage signal required to drive the motor.

This system is also capable of self-diagnostics. Error codes are stored in the microprocessor memory and displayed on the control assembly.

CONTROL ASSEMBLY

The control panel consists of 11 push buttons, a variable blower speed knob for manual selection, a Vacuum Fluorescent Display (VFD) to display set temperature, ambient temperature, diagnostic codes, and air discharge/function selection.

When system is operating under automatic control, display window will show preferred or target temperature to which the elements of the control system respond. Blower speed varies in response to ambient temperature changes and a predetermined delay factor. Set temperature can be raised or lowered in one degree increments between 65°-85°F (18°-29°C) through the use of Red (raise temperature) and Blue (lower temperature) buttons.

Control panel features include a 60°F (16°C) setting for maximum cooling and a 90°F (32°C) setting for maximum heating. An "OUTSIDE TEMP" button which will result in a 4-second display of outside air temperature. An "OFF" button which will apply vacuum to close the fresh-recirculated air door, interrupt blower motor operation, and discontinue operation of climate control system. (Scheme 1)

In automatic mode, blower speed will vary as required to maintain interior temperature. If the blower motor thumbwheel control is moved while in automatic mode, blower speed will remain under manual control until automatic is selected again.

Scheme 1

"OFF"

Blend door remains fixed. Floor-panel door directs air to plenum. Panel-defrost door is fixed in defrost position. Fresh-recirculate door moves to recirculate position. Blower and A/C clutch are off.

Blend door moves to maintain selected temperature. Blend door is in heat position when sensors are cool; door is in the A/C position when sensors are hot.

Floor-panel door moves to floor during heating, to instrument panel registers during cooling, and in mid-position between heating and cooling. Panel-defrost door moves to defrost during heating, and to panel during cooling.

Fresh-recirculate door is fixed in recirculate when engine temperature is below 120°F (49°C) and heating is required. The door recirculates air when maximum A/C is needed; otherwise, outside air flows to passenger compartment.

Blower will vary speed in response to need to maintain selected temperature. Variable blower speed is possible only when coolant temperature is above 120°F (49°C), or when A/C is required. Blower is off when coolant temperature is below 120°F (49°C) and heating is required.

A/C clutch is engaged in "AUTO" mode if outside temperature is above 50°F (10°C).

"MAX A/C"

System will engage high blower speed with a maximum cool discharge temperature. Blend door moves to recirculate position.

"COOLER" & "WARMER"

These Blue and Red buttons will raise or lower temperature in one degree increments. For maximum cooling, temperature will move from 65°F (18°C) to 60°F (15°C) in one step. For maximum heating, temperature will jump from 85°F (29°C) to 90°F (32°C) in one step.

"OUTSIDE"

This button will display outside temperature for 4 seconds and will then change back to previous display. Temperature can be displayed in Celsius or Fahrenheit.

"FLOOR-DEFROST"

This provides a mixed position with air divided between floor and defroster nozzles. Some air will bleed from side window demisters.

"DEFROST"

Most of the heated air is directed from the defroster vents. Some air is bled to the floor and side window demister.

"VENT"

System will operate with fresh air from the instrument panel registers. A/C compressor clutch turns off.

"PANEL/FLOOR"

Air is discharged equally between instrument panel registers and floor. A/C compressor clutch should be on.

Ambient Temperature Sensor Operation

Sensor contains a thermistor (temperature sensitive resistor) which measures outside air temperature and inputs signal to the EATC control assembly. Ambient temperature sensor is located in front of condenser, on left side of vehicle.

In-Vehicle Temperature Sensor

Sensor contains a thermistor (temperature sensitive resistor) which measures inside vehicle air temperature and inputs signal to the EATC control panel. In-vehicle sensor is located behind instrument panel, above glove box.

Sunload Sensor

Sunload sensor contains a photovoltaic (sunlight sensitive) diode. Sensor measures amount of sunlight entering vehicle's interior, and inputs signal to the EATC control panel. Sensor is located in left radio speaker grille assembly.

Blower Speed Controller

Blower speed controller is located in the evaporator case, upstream of evaporator core. The high-speed blower relay is located on upper half of evaporator case.

The controller converts low current signals from control panel to a high current, variable ground feed to the blower motor. Blower motor speed is infinitely variable and is controlled by the control panel software and blend door actuator position. A delay function provides a gradual increase or decrease in blower motor speeds under all conditions. There is a high blower relay integral with the blower speed controller which gives maximum airflow in high blower position.

Note. System should not be operated with blower motor disconnected. Damage may occur to blower speed controller if cooling air is not provided by the blower motor.

Cold Engine Lock-Out (CELO) Switch

This switch prevents blower operation when engine coolant is below 120°F (49°C) and 90°F (32°C) is selected (maximum heat). Switch is located in-line in heater hose to the heater core (may be inside plenum). On 3.0L engine, CELO is on right side of engine next to idle speed control solenoid.

BLEND DOOR ACTUATOR OPERATION

The blend door actuator is located on top of evaporator assembly. It controls blend door movement according to command from control assembly. An electronic circuit positions blend door by means of an electric motor. A separate potentiometer feeds the blend door position information back to control assembly.

PRESSURE RELIEF VALVE OPERATION

This valve relieves pressure build-ups above 450 psi (32 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 OPERATION

Three vacuum actuators control movement of the air distribution. Two of the vacuum actuators are mounted on plenum. One of these actuators controls movement of the floor-panel door to provide full vacuum, partial vacuum, or no vacuum. The other actuator provides full vacuum and no vacuum positions for panel-defrost door.

The third vacuum actuator is mounted on the fresh-recirculated air duct and controls movement of the fresh-recirculate air door. The electric blend door actuator is mounted on evaporator case and provides automatic control over blend door movement.

A/C Compressor Clutch

In any mode where the A/C compressor clutch operates, the compressor clutch signal is controlled by integrated relay control module (front of engine compartment, on upper radiator support). This module controls the compressor clutch relay. The Electronic Engine Control IV (EEC-IV) module will override the A/C control assembly commands and disengage the compressor clutch during wide open throttle acceleration.

Note. See appropriate ENGINE PERFORMANCE article for more information on the EEC-IV system.

Clutch Cycling Pressure Switch

This pressure sensitive switch controls the compressor clutch circuit based on evaporator core pressure. The switch controls evaporator core temperature to prevent evaporator icing. Switch opens when suction pressure is about 22 psi (1.5 kg/cm 2 ), and switch closes when suction pressure rises to about 45 psi (3 kg/cm 2 ).

Preliminary Information & Test Sequence

1. Perform EATC SELF-DIAGNOSTIC TEST. Record all error codes displayed during self-test. If error codes appear, follow diagnostic procedures outlined for each error code recorded.
2. If a malfunction exists but no error code appears, follow procedures outlined in EATC SYSTEM FUNCTIONAL TEST and DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO ERRORS FOUND test. EATC SYSTEM FUNCTIONAL TEST is designed to catch those system failures that the self-test is unable to test.

EATC SELF-DIAGNOSTIC TEST

Note. Ensure coolant temperature must be at least 120°F (49°C) before entering self-diagnostics.

Entering Self-Diagnostics

1. Depress "OFF" and "FLOOR" buttons simultaneously, and then press "AUTO" button within 2 seconds. Test may run as long as 20 seconds, at which time the display will be blank.
2. If display is blank for more than 20 seconds, go to DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO ERRORS FOUND test. Self-diagnostics can be initiated at any time with the resulting error codes being displayed. Normal system operation is stopped when system is in self-diagnostic mode.
3. To exit self-diagnostics, depress cooler button. (Scheme 1) The self-diagnostics should be deactivated before powering system down. Repair all error codes in order, from lowest number to highest number.

Code "01" - Control Panel Problem

If error code "01" appears, replace control panel. See specific REMOVAL & INSTALLATION (R & I) procedures in this article.

Code "02" - Blend Door Problem

1. Unplug both control panel connectors. Check blend door actuator movement. Turn ignition on, with engine off.
2. On 8-pin connector, attach a jumper wire from Black wire to Dark Blue/Light Green. (Scheme 5), (Scheme 6) and (Scheme 7). Disconnect jumper wire from Dark Blue/Light Green wire and connect to Orange wire terminal. Blend door should move in both directions.
3. If blend door actuator does not operate in both directions, go to step 4). If actuator operates in both directions, plug in control panel connectors and retest system using EATC FUNCTIONAL TEST. If test is successful (no error code "02"), end test.
4. If blend door actuator did not move in step 3), check blend door feedback potentiometer. Turn ignition off. Check resistance between specified wire terminals on 12-pin control assembly connector. See BLEND DOOR FEEDBACK POTENTIOMETER TEST table. BLEND DOOR FEEDBACK POTENTIOMETER TEST 12-Pin Connector Wires (1) Resistance In Ohms Light Green/Orange & Orange/Black 5000-7000 Orange/White & Orange/Black 300-7300 Orange/White & Light Green/Orange 300-7300 (1) Test with connectors unplugged and ignition off.
5. If resistances in step 4) are okay, replace control assembly. Check system function using EATC SYSTEM FUNCTIONAL TEST. If resistances were NOT correct, go to step 6).
6. Unplug both control assembly connectors and blend door actuator connector. Check wiring between control assembly and blend door actuator for continuity and shorts. (Scheme 5), (Scheme 6), and (Scheme 7).
7. If continuity checks in step 6) are NOT okay, repair or replace wiring harness. If continuity checks are okay, replace blend door actuator. Retest system using EATC SYSTEM FUNCTIONAL TEST.

Code "03" - In-Car Temperature sensor

1. Symptoms associated with this code are cold air being discharged when heat is selected, or warm air discharged when A/C is selected. Unplug in-car temperature sensor. Measure resistance across sensor terminals. See IN-CAR & AMBIENT TEMPERATURE SENSOR RESISTANCE table. IN-CAR & AMBIENT TEMPERATURE SENSOR RESISTANCE Temperature °F (°C) Resistance In Ohms 50-68 (10-20) 37,000-58,000 68-86 (20-30) 24,000-37,000 86-104 (30-40) 16,000-24,000
2. If sensor resistance is NOT as specified, replace sensor. If sensor resistance is okay, remove negative battery cable. Check wiring between sensor and control assembly for shorts or open. Repair as necessary.

Code "04" - Ambient Temperature Sensor

1. Symptoms associated with this code are that outside temperature display reads "-40°" or "140°". Also, check for cold air being discharged when heat is selected, or warm air being discharged when A/C is selected.
2. Disconnect negative battery cable to reset outside temperature display. Unplug wiring harness at sensor. Measure resistance across sensor terminals. See IN-CAR & AMBIENT TEMPERATURE SENSOR RESISTANCE table.
3. Replace sensor if resistance is not as specified. If resistance is okay, keep battery cable disconnected. Unplug connector from control assembly. Check wiring between ambient temperature sensor and control assembly for shorts or opens. Repair as necessary.

Code "05" - Sunload Sensor

1. Disconnect negative battery cable. Unplug wiring harness at sensor and from control assembly. Check wiring for continuity, shorts, and opens. Repair as necessary.
2. Sensor is a photo diode and can be checked with an ohmmeter. With harness disconnected, there should be some resistance present across sensor terminals, depending on amount of light available. If resistance is 0 (zero), replace sensor.

Code "888" - No Fault Found

If error code "888" appears, perform EATC SYSTEM FUNCTIONAL TEST.

EATC SYSTEM FUNCTIONAL TEST

Note. Perform this test if EATC SELF-DIAGNOSTIC TEST showed no error codes, but system fault still is present.

1. Ensure engine is cold and in-vehicle temperature is greater than 50°F (10°C). Turn ignition switch to "RUN" position. Press "AUTO" button and set temperature display to "90°F". If control panel powers up, go to step 2). If control panel does not light, go to DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO ERRORS FOUND test.
2. Verify that blower motor does not come on with engine temperature below 120°F (49°C). If blower motor does not come on, go to step 3). If blower motor comes on, go to COLD ENGINE LOCK-OUT SWITCH INOPERATIVE test under BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY.
3. Start engine. Ensure coolant temperature is above 120°F (49°C). Remainder of step can be performed with key on and engine off. Set temperature display to "75°F". If blower motor comes on, go to step 4). If blower motor does not come on, go to NO BLOWER test under BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY DIAGNOSIS.
4. Rotate blower speed knob fully down. If blower motor goes to low speed, go to step 5). If blower motor does not go to low speed, go to BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY test. NOTE: Before going to step 5), check battery voltage. If voltage reading is below 10 volts, check charging system.
5. Rotate blower knob fully up. If blower motor goes to high speed, go to step 6). If blower motor does not go to high speed, go to BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY test.
6. Press defrost button. Verify that air is discharged from defroster nozzle with a small amount of air bleed through side window demisters. Also verify that the fresh-recirculated air door is in the fresh air position.
7. If air discharge and fresh-recirculated air door position is correct, go to step 8). If air is not discharged through defroster or side window demisters, go to VACUUM SYSTEM test.
8. Press "FLOOR" button. If air is discharged through floor air ducts, go to step 9). If air discharge is not through floor air ducts, go to VACUUM SYSTEM test.
9. Press "VENT". If air discharge is through panel ducts, go to step 10). If air discharge is not through panel ducts, go to VACUUM SYSTEM test.
10. Make sure ambient temperature is more than 40°F (4°C). Press "MAX A/C" button. If fresh-recirculated air door is in recirculated air position, go to step 11). If not, go to VACUUM SYSTEM test.
11. Press "VENT" button. If "VENT" display is lit and A/C compressor clutch turns off, go to step 12). If A/C compressor clutch remains on, go to A/C COMPRESSOR CLUTCH DOES NOT DISENGAGE WHEN IN OFF POSITION test.
12. Press "MAX A/C" button again. If "MAX A/C" lights up and A/C compressor clutch comes on, go to step 13). If A/C compressor clutch remains off, go to NO A/C COMPRESSOR CLUTCH OPERATION test.
13. Press "AUTO" button. Verify that "AUTO" lights up. If okay, end test. If not, go to DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO ERRORS FOUND test.

DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO ERRORS FOUND

If self-diagnostics and EATC SYSTEM FUNCTIONAL TEST do not locate problem, refer to symptoms listed. Perform outlined test procedures below in SYMPTOM TROUBLE SHOOTING or service as required.

Cool Air Discharge When System Is Set To 90°f In "AUTO" Mode

Check coolant level and heater system for possible malfunction. Check blend door shaft attachment, door position, and blend door actuator. Blend door may not be in maximum heating position.

Warm Air Discharge When System Is Set To 60°f In "AUTO" Mode

Check refrigerant level and A/C compressor clutch engagement. See NO A/C COMPRESSOR CLUTCH OPERATION test. Check blend door shaft attachment, door position, and blend door actuator. Blend door may not be in maximum cooling position. Fresh-recirculated air door not in recirculation position. Check vacuum system.

Cool Air Discharge In 85°f, Maximum Heat In 90°f

Shorted sensor or wiring. Replace sensor or repair wiring.

Heated Air Discharge In 65°f, Cool Air Discharge In 60°f

Open sensor or wiring. Replace sensor or repair wiring.

No Blower

Faulty cold engine lock-out switch. See BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY DIAGNOSIS - NO BLOWER test. Check wiring, blower motor, blower speed controller, or control assembly for possible malfunction.

Blower Operates In High-Speed Only

See BLOWER SPEED CONTROLLER & HIGH-SPEED BLOWER RELAY DIAGNOSIS - BLOWER OPERATES IN HIGH-SPEED ONLY test. Check wiring, or blower speed controller for possible malfunction.

A/C Compressor Clutch Is On When In The "OFF" Position

See A/C COMPRESSOR CLUTCH DOES NOT DISENGAGE WHEN IN OFF POSITION test. Check wiring or components for possible malfunction.

Control Panel Digits & VFDS Do Not Light Up, Blower Off

1. Check fuses. Battery and ignition circuits to control assembly open. Open ground circuit to control assembly. Defective control assembly. Repair or replace as necessary.
2. Control assembly is grounded at left front side of engine compartment, at radiator support.

Cold Air Is Delivered During Heating When Engine Is Cold

1. Check cold engine lock-out (engine coolant temperature) switch for damage. Replace if necessary. If switch is okay, press "AUTO" button and set temperature display to "90°F".
2. With ignition off, ground Yellow/White wire at cold engine lock-out switch. Switch is located in-line in heater hose, or on 3.0L engine, switch is on right side of engine next to idle speed control solenoid.
3. Start vehicle. If blower motor is off, replace cold engine lock-out switch. If blower motor comes on, check wiring. If okay, replace control assembly.

Set Temperature Does Not Return To Set Position After Turning Ignition Off

Battery circuit to control assembly open. To check circuit, unplug control panel 8-pin connector. With ignition off, check for 12 volts at pin No. 12 (Light Green/Purple wire). (Scheme 5), (Scheme 6) and (Scheme 7). If voltage is present, replace control assembly. If not, check fuse and wiring.

Temperature Display Will Not Switch From Fahrenheit To Celsius

Short pin No. 20 (Red wire) of control assembly 12-pin connector to ground. (Scheme 3) Turn ignition on, with engine off. If display does not switch from Fahrenheit to Celsius, Red wire is open at control assembly or control assembly is damaged. Otherwise, check wiring and trip minder.

System Does Not Control Temperature

In-car temperature sensor hose disconnected or damaged, sensor seals missing or improperly installed, aspirator not secured to evaporator case. Repair or replace as necessary.

EATC Control Panel Turns On And Off Erratically, No Control Of System

Check for damaged charging system. EATC will not function with too low or too high battery voltage. Check battery voltage. If battery voltage is less than 10 volts or greater than 16 volts, a charging system problem exists. Do not replace EATC control panel.

NO A/C COMPRESSOR CLUTCH OPERATION

1. If compressor clutch does not operate, check for low refrigerant charge. Recharge is necessary.
2. Remove A/C compressor clutch coil connector at coil. Battery voltage should be present in any mode where A/C clutch should be operating. If battery voltage is present, but clutch does not engage, replace clutch coil.
3. If battery voltage is not present, check clutch cycling pressure switch. Switch opens when suction pressure is about 22 psi (1.5 kg/cm 2 ), and switch closes when suction pressure rises to about 45 psi (3 kg/cm 2 ). Replace switch if faulty.
4. If clutch cycling pressure switch is okay, check wiring to control assembly, check integrated control module, and A/C clutch diode. Fault may be in EEC-IV system. EEC-IV control module cuts out the A/C compressor clutch during wide open throttle operation.

COMPRESSOR CLUTCH DOESN'T DISENGAGE IN "OFF" POSITION

Unplug 8-pin control panel connector. If A/C compressor clutch disengages, replace control assembly. If A/C compressor clutch stays on, check for faulty wiring, cycling clutch pressure switch, integrated controller, or EEC-IV module.

1. Ensure ignition switch is in the "RUN" position, system is in "AUTO" mode, and display is in the "90°F" setting.
2. Change temperature setting to "60°F". If blower motor comes on, continue with this step. If not, go to step 3). Disconnect Cold Engine Lock-Out (CELO) switch and change temperature setting back to "90°F". If blower motor comes on, replace faulty CELO switch. If blower motor remains off, CELO switch wiring is grounded. Repair as necessary.
3. Connect digital voltmeter between blower speed controller Orange/Red wire and ground pin (Black wire). If reading is zero volts, check fuse and circuit wiring through high-speed blower relay. If reading is more than 10 volts, go to step 4).
4. Connect digital voltmeter between blower speed controller Tan/Orange wire and ground (Black wire). If reading fluctuates at less than 3 volts, go to step 5). If reading fluctuates at more than 3 volts, go to step 6).
5. Connect digital voltmeter between blower speed controller Orange/Red wire and ground (Black wire). If reading is less than one volt, check battery feed to blower motor or for faulty motor. If reading is more than one volt, replace blower speed controller.
6. Connect digital voltmeter between control assembly pins No. 23 (Tan/Orange wire) and No. 24 (Black wire). If reading is more than 3 volts, replace control panel. If reading is less than 3 volts, check circuit wiring through high-speed blower relay.

1. Unplug blower speed controller connector. If blower motor continues to operate in high-speed, wiring or blower motor is defective. If blower motor goes off, go to step 2).
2. Connect harness to blower speed controller. Place system in "AUTO" mode and rotate blower switch from high to low.
3. Connect digital voltmeter between blower speed controller pin No. 2 (Tan/Orange wire) and ground pin No. 4 (Black wire). If reading fluctuates at less than 7 volts, replace control assembly. If reading fluctuates at more than 7 volts, replace blower speed controller.

Cold Engine Lock-Out Switch Inoperative

1. Ensure coolant temperature is below 120°F (49°C), system is in "AUTO" mode, and temperature set to "90°F". If blower motor comes on, check coolant temperature and retest.
2. If blower motor comes on with engine cold, replace cold engine lock-out (engine coolant temperature) switch. If blower motor is off, cold engine lock-out switch is okay.

Blower Operates But Does Not Vary With Blower Control Switch

1. Connect digital voltmeter between blower speed controller pin No. 2 (Tan/Orange wire) and ground pin No. 4 (Black wire). Place system in "AUTO" mode and rotate blower switch from low to high, and then back to low.
2. If reading fluctuates from less than 7 volts, to more than 7 volts, and then back to less than 7 volts, go to step 3). If reading does not fluctuate, replace control panel.
3. Connect digital voltmeter between blower speed controller Light Blue/Pink wire and Black wire. Place system in "AUTO" mode and rotate blower switch from low to high.
4. If reading changes from less than one volt to 7 volts, check battery feed to blower motor or for faulty motor. If voltmeter reading does not change, replace blower speed controller.

VACUUM SYSTEM

1. Start engine and depress control assembly function buttons slowly from one position to another. A momentary hiss should be heard as each button is pressed. Hissing sound indicates that vacuum is available at control panel.
2. If hiss is not heard, check for a kinked, pinched, or disconnected vacuum supply hose. Also inspect check valve between intake manifold and vacuum reservoir to ensure it is working properly. NOTE: A continuous hiss at control panel indicates a major vacuum leak somewhere in system. It does not necessarily indicate that leak is at control panel.
3. If momentary hiss is heard as each function button is pressed, vacuum is available at control panel. Cycle function buttons through each position with blower on high position and check air discharge at ducts.
4. If a vacuum motor fails to operate, motor can be identified as airflow at ducts will be incorrect. (Scheme 2) If vacuum motor is inoperative, apply vacuum to motor. If motor operates, check vacuum hose (going to motor) for leaks or other damage.
5. If vacuum system works normally at idle, but goes to defrost during acceleration, a small leak exists in vacuum system. Leak can be best located by shutting engine off and using a vacuum gauge to check for vacuum loss while selectively blocking off vacuum hoses.

Scheme 2

SENSORS

See error codes 03, 04 and 05 under ERROR CODE DIAGNOSIS.

Removal

Discharge A/C system using approved refrigerant recovery/recycling equipment. Insert appropriate spring lock coupling clamp over fitting. (Scheme 3) Close clamp and push into cage to release female fitting from garter spring. After garter spring has expanded, pull coupling apart. Remove spring lock coupling clamp from line.

Installation

Ensure garter spring is in cage of male fitting. If garter spring is missing or damaged, install new garter spring. Install new "O" rings and lubricate with clean refrigerant oil. Push fittings together until garter spring is over flared end of female fitting. Pull on female fitting and verify position of garter spring.

Scheme 3

1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Drain cooling system and disconnect negative battery cable. Disconnect and remove integrated relay controller. Remove fan shroud assembly, radiator hose, and radiator.
2. Disconnect A/C compressor clutch wiring. Raise vehicle on hoist. Loosen and remove compressor drive belt. Disconnect exhaust gas temperature sensor wiring. Remove A/C muffler support strap bolt from frame.
3. Disconnect refrigerant lines from condenser and receiver-drier. Cap all openings. Support compressor and remove compressor mounting bolts. Remove compressor, manifold, and tubes as an assembly. Remove manifold, tubes, and clutch from compressor.

To install, reverse removal procedure. Before installing new compressor, drain 4 ounces of refrigerant oil from compressor. Evacuate and charge A/C system.

1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect A/C compressor clutch wiring. Loosen drive belt. Disconnect hoses from condenser and suction line. Cap all openings.
2. Remove 4 compressor mounting bolts. From top of vehicle, remove compressor, manifold, and tubes as an assembly. Remove manifold, tubes, and clutch from compressor.

To install, reverse removal procedure. Before installing new compressor, drain 4 ounces of refrigerant oil from compressor. Evacuate and charge A/C system.

Removal & Installation

Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect refrigerant lines on right side of radiator. Remove 4 bolts attaching condenser to radiator support. Remove condenser. To install, reverse removal procedure. Evacuate and charge A/C system.

1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect suction line from compressor. Disconnect inlet tube from evaporator core outlet. Cap all openings to keep moisture out.
2. Disconnect wiring from pressure switch on top of receiver-drier. Remove screw and receiver-drier. To install, reverse removal procedure. Evacuate and charge A/C system.

1. Disconnect negative battery cable. Remove 4 steering column cover screws and cover. Remove sound insulator by removing nuts from studs on evaporator case. Remove steering column trim shrouds. Unplug connectors from steering column switches.
2. Remove bolt and nut from steering shaft "U" joint. Remove 4 screws and steering column. Remove lower left and radio trim panels. Remove 5 instrument cluster retaining screws.
3. Release instrument cluster trim panel by rocking upper edge of panel toward driver's seat. Disconnect speedometer cable. Release glove box assembly by pressing side of glove box bin and swinging assembly downward.
4. Disconnect vacuum hoses, wiring harness, radio antenna cable, and A/C-heater control cable by reaching through steering column, instrument cluster, and glove box openings.
5. Disconnect wiring harness on engine compartment side. Disengage rubber grommet from firewall. Feed main wiring harness and connectors through opening and into instrument panel area.
6. Snap out right/left speaker covers and defroster grille. Remove 3 upper and lower instrument panel retaining screws (one screw is located above left side of transmission tunnel). Remove instrument panel. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove 4 steering column cover screws and cover. Remove sound insulator by removing nuts from studs on evaporator case. Remove steering column trim shrouds. Unplug connectors from steering column switches.
2. Remove 4 steering column bracket mounting bolts. Lower steering column. Remove lower left and radio trim panels. Remove 7 instrument cluster trim panel retaining screws. Remove jam nut from behind headlight switch knob.
3. Remove screws from behind clock or clock cover. Release trim panel by rocking upper edge of panel toward driver's seat. Disconnect speedometer cable. Release glove box assembly by pressing side of glove box bin and swinging assembly downward.
4. Disconnect vacuum hoses, wiring harness, radio antenna cable, and A/C-heater control cable by reaching through steering column, instrument cluster, and glove box openings.
5. Disconnect wiring harness on engine compartment side. Disengage rubber grommet from firewall. Feed main wiring harness and connectors through opening and into instrument panel area.
6. Snap out right/left speaker covers. Remove 3 upper and lower instrument panel retaining screws (one screw is located under radio). Remove instrument panel. To install, reverse removal procedure.

1. Disconnect negative battery cable. Drain cooling system and discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect hoses from heater core. Plug heater core tubes and blow out coolant from core. (Scheme 4)
2. Disconnect vacuum supply hose from in-line vacuum check valve in engine compartment. Disconnect liquid line and accumulator from evaporator core. Plug all openings.
3. Remove instrument panel. Remove instrument panel shake brace from evaporator case. Remove 2 screws attaching floor register or rear seat adapter to bottom of evaporator case.
4. Remove 3 nuts (in engine compartment) attaching evaporator case to firewall. Remove 2 screws attaching support brackets to cowl top panel. Carefully pull evaporator case away from firewall. To install, reverse removal procedure.

Scheme 4

1. Remove evaporator case. Disconnect and remove vacuum harness. Remove 6 screws and recirculation duct from evaporator case. Remove 2 screws and air inlet duct from evaporator case.
2. Remove evaporator case support bracket. Remove screw attaching connector bracket to recirculation duct. Disconnect high-speed blower relay lead from blower speed controller. (Scheme 4)
3. Free 3 connectors from bracket and remove bracket. Remove screws and high-speed blower relay. Remove 3 screws and blend door actuator. Remove cold engine lock-out switch from heater core tube.
4. Remove molded seals from evaporator core tubes. Drill a 3/16" hole in each of the 2 upright tabs on top of evaporator case. Using a small saw, cut top of evaporator case between raised outlines. Fold cutout back and remove evaporator core.

Transfer core seals to new evaporator core. Install evaporator core into evaporator case. Install spring nut on both upright tabs. Install screws into spring nuts to secure cover. Using Caulking Cord (D9AZ-19560-A), seal evaporator case along cut line. To install, reverse removal procedure.

1. Remove instrument panel and evaporator case. Remove vacuum line from heater core tube seal. Remove seal from heater core tubes. Remove 3 screws attaching blend door actuator to evaporator case.
2. Remove actuator and cold engine lock-out switch from case. Remove 4 heater core access cover mounting screws, access cover, seal, and heater core from evaporator case. To install, reverse removal procedure.

1. Open glove box, release retainers, and lower door. Remove screw attaching recirculation duct support bracket to cowl. Remove screw attaching connector bracket to recirculation duct.
2. Free 3 connectors from bracket and remove bracket. Disconnect vacuum hose to recirculation door vacuum motor. Remove 6 screws attaching recirculation duct to evaporator case.
3. Remove recirculation duct from evaporator by lowering it between instrument panel and evaporator case. Unplug blower motor connector. Remove blower motor push nut and fan. (Scheme 4) Remove 4 screws and blower motor. To install, reverse removal procedure.

Lower glove box door to provide access to recirculation duct assembly. Disconnect vacuum hose from end of vacuum motor. Detach motor arm retainer from door crank arm. Remove nuts and vacuum motor. To install, reverse removal procedure.

Disconnect negative battery cable. Remove instrument panel. Detach vacuum motor arm from door shaft. Disconnect vacuum hose from actuator. Remove nuts and actuator. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove lower left and right instrument panel finish inserts. Remove 8 upper finish panel retaining screws and upper finish panel. Remove 4 control panel screws.
2. Pull control panel out to gain access to connectors. Unplug connectors from control panel. Remove 2 nuts from vacuum connector and remove control panel. To install, reverse removal procedure.

Disconnect negative battery cable. Remove left radio speaker grille. Remove 2 sunload sensor mounting nuts. Unplug electrical connector and remove sunload sensor. To install, reverse removal procedure.

Disconnect negative battery cable. On Sable, remove glove box. On Taurus, remove lower right instrument finish panel. On either model, remove in-car temperature sensor mounting screws. Unplug electrical connector, carefully disconnect aspirator hose, and remove sensor. To install, reverse removal procedure.

Disconnect negative battery cable. Remove ambient sensor nut and sensor (sensor is located on condenser, on right side of vehicle). Unplug electrical connector. To install, reverse removal procedure.

1. Disengage glove box door stops and allow door to hang by hinge. Working through glove box opening, unplug electrical connector and hose at blower speed controller. Free connector from its mounting bracket.
2. Remove screws attaching blower speed controller to evaporator case and remove controller. DO NOT touch controller fins as they may be HOT. To install, reverse removal procedure.

1. Reach behind instrument panel to a point above and slightly to right of accelerator pedal. Locate outermost heater core tube. Locate switch wires and firmly pull them downward until spring clip is released from heater core tube.
2. Cut both White and Yellow/White wire 4-5" away from base of switch. Attach replacement switch to wiring and crimp in place. Wire polarity is not critical.
3. Grasp new switch by base and carefully snap it into place on heater core tube. If switch attaches on its side, performance will not be affected. Route wires through guide on evaporator case.

1. Disconnect negative battery cable. Loosen instrument panel and pull back from cowl. Free blend door actuator connector from bracket on evaporator case.
2. Remove 3 actuator attaching screws and cold engine lock-out switch from heater core tube. Lift actuator vertically 1/2" to disengage it from bracket and blend door shaft. Pull actuator toward passenger compartment.

To install, reverse removal procedure. After actuator is installed, disconnect positive battery cable. After 30 seconds, reconnect cable to terminal. Actuator adjustment will be performed automatically.

1988 Sable & Taurus EATC Wiring Diagram. Scheme 5

1989 Sable & Taurus EATC Wiring Diagram (1 of 2). Scheme 6

1989 Sable & Taurus EATC Wiring Diagram (2 of 2). Scheme 7

1990 Sable & Taurus EATC Wiring Diagram (1 of 2). Scheme 8

1990 Sable & Taurus EATC Wiring Diagram (2 of 2). Scheme 9