A/C SYSTEM SPECIFICATIONS
| Application | Specification | |
|---|---|---|
| Compressor Type | Harrison (Frigidaire) 6-Cyl. | |
| R-12 Capacity | (1) 38 oz. | |
| Oil Capacity | ||
| Large Condenser | 1.8 oz. | |
| Small Condenser | 1.5 oz. | |
| Evaporator | 4.0 oz. | |
| Compressor | 3.0 oz. | |
| Normal System Pressure | ||
| Low Side | (2) 18.9-24.7 psi (1.3-1.7 kg/cm 2 ) | |
| High Side | (2) Approx. 170 psi (12 kg/cm 2 ) | |
| A/C Belt Tension | ||
| New | 100 lbs. | |
| Used | 80-90 lbs. | |
| (1) When recharging system, add at least 18 oz. of refrigerant to low side port BEFORE operating compressor. (2) Operating pressures at 77°F (25°C). | ||
| (1) | When recharging system, add at least 18 oz. of refrigerant to low side port BEFORE operating compressor. |
| (2) | Operating pressures at 77°F (25°C). |
A/C SYSTEM SPECIFICATIONS
DESCRIPTION
| CAUTION | When discharging air conditioning system, use only approved refrigerant recovery/recycling equipment. Make every attempt to avoid discharging refrigerant into the atmosphere. |
The driver operates the system by pushing various buttons on A/C-heater control panel.
Like earlier systems, fresh air blower speed is controlled automatically. Blower speed will be controlled according to difference between set temperature and interior temperature.
Blower speed can also be controlled manually. Depressing the "HI" or "LO" buttons will raise or lower blower speed while in any selected mode. The "WARMER" or "COOLER" buttons are used to raise or lower selected temperature.
The digital climate control system automatically maintains temperatures set between 64°F (18°C) and 85°F (29°C). If a temperature above 85°F (29°C) is selected, the word "HI" appears in temperature display. If a temperature below 64°F (18°C) is selected, the word "LO" is displayed. Selection of these temperatures overrides automatic climate control system.
A/C SYSTEM
If the vehicle interior is hot and the climate control is programmed to maintain a temperature of 75°F (24°C), climate control will function as follows: recirculation doors open, fresh air door will close and 85% of inside air will be recirculated. Heater control valve will close and air will flow from registers. Temperature control door should be closed. No air should flow through heater core. Blower speed will increase from low to high over a 10 second period. As interior cools down, recirculation door will close as fresh air door begins to open.
If needed, heater control valve will open, the temperature control door will begin to open and blower speed will slow. Air flowing from registers warms slightly. There are 3 factors that control system operation: outside temperature, inside temperature, and temperature setting. On a hot day, the system may operate in maximum cold mode for a long time. On milder days, system may operate any place in the intermediate range.
If vehicle is very cold and climate control is programmed to maintain a temperature of 75°F (24°C), climate control will function as follows: recirculation door will close, and outside air will flow into system. Heater control valve will open, allowing coolant to flow through heater core. Air will flow from floor vents. Temperature control door will open, and all air will flow through heater core. Blower speed can be controlled manually, regardless of heater setting, by pushing "HI" or "LO" buttons.
Note. The blower delay feature is over-ridden when the defroster button is depressed. Hot air does not flow from registers. If system is in bi-level mode, warm air flows from floor vents and cooler air from registers.
"OFF" Mode
When the "OFF" button is pressed, the system is switched off. (Scheme 1) Fresh air intake is closed and temperature display is turned off. Outside temperature is shown on display.
Note. If vacuum system fails, climate control automatically switches to maximum defrost.
"ECON" Mode
In this mode, the A/C compressor is turned off. Temperature, blower speed, and air distribution are automatically regulated. Air distribution is determined by difference between actual interior temperature and selected temperature.
"AUTO" Mode
With "AUTO" button actuated, the A/C compressor is turned on. (Scheme 1) Temperature, blower speed, and air distribution are automatically regulated. Air distribution is determined by difference between actual interior temperature and selected temperature.
"BI-LEV" Mode
With bi-level mode activated, the A/C compressor is turned on. Temperature, blower speed, and air distribution are automatically regulated. Air distribution is fixed at center and footwell outlets.
Defrost Mode
In this setting, temperature and blower speed are automatically regulated. All air is directed toward windshield.
"HI" & "LO" Settings
These settings are used to raise or lower blower speed in all operating modes. The "HI" or "LO" settings are cancelled by pressing another mode button.
A/C-HEATER CONTROL PANEL
The A/C-heater control panel receives input from driver, system components, processes input signals and operates system accordingly. (Scheme 1)
Scheme 1
A/C PROGRAMMER
The A/C programmer receives input signals from A/C-heater control panel. The programmer, in turn, controls position of heater temperature regulation flaps through DC motor and cable.
The A/C programmer operates air distribution vacuum servo motors through the use of 4 vacuum solenoids. The programmer also controls A/C compressor clutch relay operation, based on input signals from A/C-heater control panel.
On 5000S models, the A/C programmer switches radiator cooling fan relay when A/C system is on. The A/C programmer is located under instrument panel, behind glove box.
A/C BLOWER CONTROL UNIT
The A/C blower control unit regulates the amount of power supplied to the fresh air blower motor depending on signal it receives from A/C-heater control panel. The A/C blower control unit is located on top of evaporator. (Scheme 2)
OUTSIDE TEMPERATURE SENSORS
Sensors measure the outside air temperature and send an input signal to the A/C-heater control panel. The A/C-heater control panel measures both sensor readings and uses the lowest temperature value to calculate correction factor for interior temperature regulation. One sensor is located in front of radiator, the other is located in evaporator plenum chamber. (Scheme 2)
IN-CAR TEMPERATURE SENSOR
The in-car temperature sensor measures interior air temperature and sends this signal to the A/C-heater control panel. A small fan drives air over sensor to ensure an accurate measurement. The in-car temperature sensor is mounted on top of instrument panel.
REFRIGERANT LOW PRESSURE SWITCH
The refrigerant low pressure switch disengages A/C compressor clutch if refrigerant pressure drops below 15 psi (1.1 kg/cm 2 ). Switch is located in suction line from A/C accumulator.
Scheme 2
REFRIGERANT HIGH PRESSURE SWITCH
This switch controls operation of cooling fan 2nd stage. Switch closes when pressure reaches 200 psi (14.1 kg/cm 2 ). Switch is located in high pressure line to A/C compressor.
A/C HIGH PRESSURE SENSOR
Sensor measures refrigerant temperature and sends resistance signal to A/C-heater control panel. If refrigerant pressure goes too high, the A/C-heater control panel will shut A/C compressor off to prevent system damage. The A/C high pressure sensor is located in plenum chamber, near left side of heat exchanger housing.
A/C THERMOSTAT
The A/C thermostat controls power supply to A/C compressor clutch relay to prevent ice from forming on evaporator. If evaporator temperature falls below 32°F (0°C) the A/C thermostat switch opens, the A/C compressor clutch relay opens, and the A/C compressor clutch disengages. The A/C thermostat is located on evaporator housing, with its capillary tube inserted in evaporator.
AMBIENT TEMPERATURE SWITCH
The ambient temperature switch interrupts ground signal, preventing the A/C-heater control panel from engaging the A/C compressor clutch. The switch opens when ambient temperature falls below 37°F (3°C). The ambient temperature switch is located on top, left corner of evaporator housing. (Scheme 2)
A/C KICK-DOWN SWITCH
The switch closes and sends a ground signal to terminal No. 9 of A/C-heater control panel when accelerator pedal is floored. This will turn the A/C compressor on for about 12 seconds. The A/C kick-down switch is located under accelerator pedal on vehicles equipped with automatic transmissions.
ENGINE COOLANT OVERHEAT SWITCH
When coolant temperature goes over 247°F (120°C), this switch sends a ground signal to terminal No. 20 of A/C-heater control panel. The A/C-heater control panel then sends a signal to A/C programmer, which in turn disengages the A/C compressor clutch. The engine coolant overheat switch is part of the electronic thermoswitch, located on cylinder head coolant flange.
HEATER FLAP
- Disconnect heater flap cable at A/C programmer. Inner cable end must not come up against lever arm. (Scheme 3) Loosen cable clip on heat exchanger housing and start engine.
- Set A/C-heater control panel to "AUTO" position and temperature at 90°F (32°C). Wait 2 minutes. Install heater flap cable on A/C programmer. Push cable sleeve in direction of arrow until heater flap for temperature regulation comes up against stop. Install cable clip.
Scheme 3
Check continuity of wires between panel and A/C programmer. (Scheme 5) Terminals No. 3, 10, 21, and 22 form a multiple connection with A/C programmer. The input signals at these terminals cannot be checked. (Scheme 4)
Scheme 4
A/C-Heater Control Panel Signals. Scheme 5
- Check continuity of wire terminals No. 4, 6, 9, and 12 with A/C-heater control panel. Check for correct output signals from A/C-heater control panel.
- Terminals No. 4, 6, 9, and 10 form a multiple connection with A/C-heater control panel. The input signals at these terminals cannot be checked. (Scheme 7)
Scheme 6
A/C Programmer Signals. Scheme 7
OUTSIDE TEMPERATURE SENSOR
Unplug outside temperature sensor connector. Using ohmmeter, check sensor resistance and compare reading with specifications. (Scheme 6) If incorrect, replace sensor.
Scheme 8
Unplug A/C thermostat connector. Using ohmmeter, check sensor resistance and compare reading with specifications. (Scheme 9) If incorrect, replace sensor.
Scheme 9
Removal & Installation
Remove upper half of middle console, glove box, and lower dashboard cover. Remove 2 screws below control panel. Push panel forward and remove from below. To install, reverse removal procedure.
Removal
- From engine compartment, loosen water drain hose retainer and push hose into plenum chamber. Disconnect vacuum unit hose and thermostat wires. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove refrigerant hoses, and plug openings.
- From inside vehicle, remove lower dash panel. Remove 4 evaporator housing screws around air vent on evaporator unit.
- From engine compartment, carefully loosen assembly. Pull evaporator assembly up and toward center of vehicle to remove. Separate housing halves to service evaporator.
Installation
Assemble evaporator case. Insert assembly into plenum chamber. Place drain hose through hole without kinking it. Clamp into place. Attach refrigerant lines loosely, and cement gasket into place around opening. Install screws, tighten hoses, and recharge system.
- From engine compartment, disconnect battery cable, thermostat wiring, evaporator-heater duct clamp, temperature control cable and vacuum hose.
- Remove electrical wiring, loosen restraining strap and remove coolant reservoir cap. Clamp heater hoses closed near heater core. Disconnect hoses from core. Upper hose goes to water pump, lower to cylinder head.
- From inside vehicle, disconnect vacuum lines. Disconnect air ducts and electrical wiring. Remove 4 screws around evaporator housing opening. Lift heater assembly up into engine compartment. Remove grommet and control cable. Loosen clips and wiring harness.
To install, reverse removal procedure. Seal all air duct connections carefully to prevent air leaks.
