Automatic A/c-Heater Systems: Other Lincoln LS I

DATC MODULE

Note. May also be referred to as EATC or DEATC module.

DATC module consists of a digital display, individual temperature set controls, mode control buttons (manual override), and a blower speed control button. The temperature can be increased with up arrow button up to 85°F (29°C) or decreased with down arrow button down to 65°F (18°C). see scheme 1 DATC contains an On-Board Diagnostic (OBD) feature to provide technician with DTCs to aid with diagnosing system faults. Mode buttons on lower edge of DATC module override automatic function. The override buttons affect operation as follows

OFF Button

When OFF is selected, inlet air door moves to recirculated air position, floor door opens, all other doors move to closed position. Coolant control valve closes to shut off coolant flow to heater core. Electric water pump turns off (if equipped). Blower motor and compressor are off.

Automatic Button

When AUTOMATIC setting is selected, AUTO and set temperature will be shown in the DATC display window. System maintains set temperature by controlling airflow direction, airflow quantity and discharge temperature required for comfort.

A/C Button

Pressing A/C button manually enables or disables A/C system in all modes except defrost and floor/defrost. Blower motor speed, air distribution and temperature will also need to be selected. A/C clutch will operate if ambient temperature is approximately 50°F (10°C) or more.

Recirculation Button

Recirculation feature is used to manually select outside or recirculated air. Recirculated air is used to help reduce amount of time it takes to cool down interior in very hot conditions. Recirculated air may also reduce unwanted odors from outside to enter vehicle. Recirculation mode cannot be selected during defrost or floor/defrost modes. In AUTO mode, recirculated air mode is controlled automatically.

Vent

When vent button is selected, only outside air is directed to instrument panel vents. No cooling is allowed, but air temperature can be heated and blower speed can be manually adjusted. Compressor will be off.

Panel

When panel button is pressed, DATC commands panel door/rear seat console door actuator to fully open position, defrost and floor outlet actuator doors to close fully. Blower motor is on. Air is directed through dash panel and rear seat console registers. Pressing A/C button will enable or disable compressor. Air can be heated or cooled using temperature control buttons.

Panel/Floor

When panel/floor button is pressed, DATC module commands defrost door to close fully, panel door/rear seat console door to open partially, floor outlet door actuator to open fully and blower motor on. Outside or recirculated air is directed through instrument panel registers and through center console rear and rear floor registers.

Floor

When floor button is pressed, DATC module commands air inlet door allows only outside air to enter, defrost door actuator to open partially, panel door/rear seat console door to close fully, floor outlet door actuator to open fully. Outside air will enter be directed through floor vents at center console and heater outlet. Temperature of air can be heated, but not cooled. Compressor is off. Blower motor speed can be manually adjusted.

Floor/Defrost

When floor/defrost button is pressed, DATC commands air inlet door to admit outside air only, defrost door to a partial open position, panel door/rear seat condole door to close fully, floor outlet door to fully open position, blower motor on and compressor will operate if ambient temperature is approximately 50°F (10°C) or more. Blower motor speed can be manually adjusted. Outside air is directed out floor and defrost ducts, with a small amount of air to side window demister vents.

FRONT Defrost

When FRONT defrost button is pressed, DATC will command air inlet door to admit only outside air, cold air by-pass door to close fully, panel door/rear seat console door and floor outlet door to close fully. Blower motor and compressor are enabled. A/C compressor will operate if ambient temperature is approximately 50°F (10°C) or more. Blower motor speed can be manually adjusted. Outside air is directed out defrost registers and side window demister vents.

AUXILIARY WATER PUMP

On 3.9L engine, the auxiliary water pump is electrically driven to provide increased engine coolant flow during low engine speed operation. Under certain conditions, the auxiliary water pump also circulates engine coolant after engine is turned off.

Ambient Temperature Sensor

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

In-Car Temperature Sensor

Sensor contains a thermistor (temperature sensitive resistor), which measures temperature inside vehicle and inputs signal to DATC module. In-car temperature sensor (automatic temperature control sensor) is located behind instrument panel, left of radio. see scheme 1

Dual Sunload Sensor

Dual sunload sensor contains a photovoltaic (sunlight sensitive) diode, which measures sunlight entering vehicle and inputs signal to DATC module. Sensor is located on top center of instrument panel, in defrost grille.

BLOWER MOTOR SPEED CONTROL

Blower motor speed control is located under evaporator housing, left of blower motor. Blower motor control converts low current signals from DATC module to a high current, variable ground feed to the blower motor. Blower motor speed is infinitely variable and is controlled by DATC module.

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

DEFROST DOOR ACTUATOR

Defrost door is located on plenum chamber. Defrost door actuator is designed to move air temperature blend doors on command from DATC module. Defrost door actuator contains a reversible electric motor and potentiometer to move temperature blend door fully open, defrost door during defrost and floor mode operation, and partially open during floor/defrost mode. A 5-volt signal is applied to ends of potentiometer, and a variable voltage at wiper arm indicates position of potentiometer, which ultimately drives actuator to proper position.

COLD AIR BY-PASS DOOR ACTUATOR

Note. May also be referred to as electronic blend door actuator.

Cold air by-pass door actuator is located on evaporator housing and is designed to move air temperature blend doors on command from DATC module. Cold air by-pass door actuator contains a reversible electric motor and potentiometer to move door. A 5-volt signal is applied to ends of potentiometer, and a variable voltage at wiper arm indicates position of potentiometer, which ultimately drives actuator to proper position.

ELECTRIC AIR INLET DOOR ACTUATOR

Electric air inlet door actuator, located on evaporator housing, determines whether outside or recirculated air is used. Electric air inlet door actuator contains a reversible electric motor and potentiometer to move door. A 5-volt signal is applied to ends of potentiometer, and a variable voltage at wiper arm indicates position of potentiometer, which ultimately drives actuator to proper position.

DUAL COOLANT CONTROL VALVE

Dual coolant valve regulates flow of engine coolant to each half of heater core. DATC module individually controls 2 electric solenoids. Dual coolant valve contains 5 ports: inlet and outlet ports (on front face of valve), outlet port to driver's side of heater core, outlet port to passenger's side of heater core, and a return port from heater core (on rear face of valve).

FLOOR OUTLET DOOR ACTUATOR

The floor outlet door actuator positions floor outlet door fully open during floor, floor/panel and floor/defrost positions. Floor outlet door remains closed during other operations. Floor outlet door actuator contains a reversible electric motor and potentiometer to move door. A 5-volt signal is applied to ends of potentiometer, and a variable voltage at wiper arm indicates position of potentiometer, which ultimately drives actuator to proper position.

PANEL/FLOOR CONSOLE DOOR ACTUATOR

Panel/floor console door actuator is located on plenum chamber. The actuator operates panel door which is mechanically linked to the floor console door. Actuator positions the panel door and floor console door fully open during panel mode and partially open during floor/panel operation. Doors remain closed during other operations. Panel/floor console door actuator contains a reversible electric motor and potentiometer to move door. A 5-volt signal is applied to ends of potentiometer, and a variable voltage at wiper arm indicates position of potentiometer, which ultimately drives actuator to proper position.

PRESSURE RELIEF VALVE

Pressure relief valve relieves high-side pressure build-up and prevents damage to A/C compressor and other system components. Pressure relief valve is located on manifold and tube assembly. Pressure relief valve opens at about 550-600 psi (38.7-42.2 kg/cm 2 ) and will close again when excess pressure is vented. Valve also prevents total loss of refrigerant.

PRESSURE TRANSDUCER

Pressure transducer (A/C cycling switch) is mounted on a Schrader valve on compressor discharge line. Pressure transducer monitors compressor discharge pressure and communicates with PCM. PCM will interrupt compressor operation if pressure transducer indicates high system discharge pressure or a no or low pressure condition. PCM will interrupt power to the compressor when pressure rises to about 420 psi (29.5 kg/cm 2 ). When pressure drops to about 250 psi (17.65 kg/cm 2 ), PCM will again supply power to compressor.

THERMOSTATIC EXPANSION VALVE

Thermostatic Expansion Valve (TXV) is mounted to evaporator core inlet and outlet tubes. TXV contains an adjustable orifice which provides the restriction that separates high pressure and low pressure liquid sides of A/C system.

DATC MODULE CONFIGURATION

Note. Modules that need programming should not be exchanged between vehicles. In most cases, the parameter values or settings are unique to that vehicle, and if not set correctly, will cause concerns or faults. Specific configurations for DATC module were not available from manufacturer.

Some modules must be programmed as part of repair procedure. If this procedure is not followed, module will not function correctly and may set a number of DTCs, including B2477 or P1639, which indicate that some necessary data has not been programmed into module.

Some PCMs contain a memory area called a Vehicle Identification (VID) block. VID block is used to store backup data for each programmable module, as well as powertrain configuration information. If diagnostic tool cannot retrieve module option content information from suspect module, diagnostic tool will attempt to extract backup information from PCM VID block. PCM VID block contains factory settings for configured modules unless PCM is flashed with a new calibration, in which case some PCM parameters may be modified.

As-Built Data Center maintains a record of vehicle configuration in a database. Vehicle VIN is required to obtain this information. As-Built Data Center records applicable module configurations stored in each module before the vehicle leaves the factory. As-Built Data Center will always reflect original build of the vehicle as it left the factory. Only contact As-Built Data Center when directed to do so by New Generation Star (NGS) tester.

Worldwide Diagnostic System (WDS) will automatically attempt to retrieve module configuration information from all modules, and from a backup location in PCM when vehicle ID is carried out. If module and the PCM do not contain correct information, scan tool will either request "as built" data or display a list of items that you will need to manually configure. Scan tool will program module based on the data entered. There are three different methods that are used for module programming (some modules do not support all three methods)

1. Programmable module installation (PMI).
2. Calibration update.
3. Programmable parameters.

Programmable Parameters

This method is used to configure parameters that can be modified in service. These are typically at preferences of the customer. Not all features controlled by a module are listed in this configuration method. See the module configuration index for a list of system features contained in the PCM memory area called a Vehicle Identification (VID) block. PCM VID block contains factory settings for configurable modules, unless PCM has been flashed with a new calibration. If a module that has been modified using programmable parameters needs to be installed, the PMI procedure will maintain parameters in their altered state, if WDS is able to communicate with the old module during vehicle identification. Otherwise programmable parameters may need to be used to return them to the altered state.

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 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-96435-S39305199672001041300000) 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-96435-S09195279392001050800000) table.

A/C SYSTEM PERFORMANCE SPECIFICATIONS

A/C SYSTEM HIGH-SIDE PRESSURE SPECIFICATIONS

HEATER CORE

1. Check for proper coolant level. Start engine and turn heater on. When engine reaches normal operating temperature, feel heater outlet hose. It should be hot. If not, heater core may have an air pocket, heater core may be plugged, or thermostat may not be working properly.
2. Drain cooling system. Disconnect heater hoses from heater core. Install a short piece of heater hose, about 4" (101 mm) long on each heater core tube. (Scheme 37)
3. Fill heater core and heater hoses with water. Install Plug (BT-7422-B) on end of hose and Adapter (BT-7422-A) on other end. (Scheme 37) Secure hoses to core tubes, plug, and adapter with hose clamps.
4. Attach pump and gauge assembly from a radiator/pressure tester to adapter fitting on heater hose. Close tester bleed valve and apply 35 psi (2.46 kg/cm 2 ) air pressure to heater core. Observe gauge for 3 minutes.
5. If pressure drops, check all hose clamp connections for proper fit; replace leaking hoses or clamps. If hoses do not leak, remove heater core from vehicle.

Scheme 36

MICRO ISO RELAY

1. Remove relay from auxiliary junction box. Ensure continuity exists between relay terminals No. 1 and 2, and between relay terminals No. 3 and 4. (Scheme 38) Continuity should not exist between relay terminals No. 3 and 5. If continuity is as specified, go to next step. If continuity is not as specified, replace relay.
2. Using a jumper wire, apply battery voltage to relay terminal No. 1. Using a second jumper wire, ground relay terminal No. 2. Continuity should now exist between relay terminals No. 3 and 5. If continuity is not as specified, replace relay. If continuity is as specified, relay is okay at this time.

Scheme 37

Scheme 38

1. Remove blower motor relay. Ensure continuity exists between relay terminals No. 85 and 86, and between relay terminals No. 30 and 87a. (Scheme 39) Continuity should not exist between relay terminals No. 30 and 87. If continuity is as specified, go to next step. If continuity is not as specified, replace relay.
2. Using a jumper wire, apply battery voltage to relay terminal No. 85. Using a second jumper wire, ground relay terminal No. 86. Continuity should now exist between relay terminals No. 30 and 87. If continuity is not as specified, replace relay. If continuity is as specified, relay is okay at this time.

A/C CYCLING SWITCH

Note. A/C cycling switch may also be called A/C pressure transducer.

Note. Control assembly has 3 pins at top of bezel assembly which pilot in bottom of radio bezel. Use caution when removing control assembly so as not to break off guide pins.

DOOR ACTUATORS

Note. New door actuator assemblies are shipped with actuator in mid-position. If reinstalling an actuator removed from vehicle, use fused jumper wires to drive actuator to mid-position to assist in assembly.

Scheme 39

1. Disconnect negative battery cable. Remove passenger's side instrument panel insulator. Remove right front floor duct. Disconnect air inlet door actuator harness connector. Remove coupling connector. Remove mounting screws and remove air inlet door actuator.
2. To install, reverse removal procedure. If reinstalling an actuator removed from vehicle, align arrow on actuator housing with line on actuator coupling. see scheme 14

INSTRUMENT PANEL