A/C-HEATER CONTROL PANEL
The A/C-heater control panel includes soft touch buttons to select operating modes, temperature control, English/Metric display switch, rear defogger switch and a vacuum fluorescent display panel. (Scheme 8)or (Scheme 9).
Scheme 8
Scheme 9
A/C-HEATER PROGRAMMER
The programmer receives signals from the A/C-heater control panel, solar sensors, ambient temperature sensor, in-vehicle temperature sensor, blower control module, Powertrain Control Module (PCM), mode selector switch and actuators. A microprocessor in the programmer processes the signals and then sends commands to the system components to control A/C compressor clutch operation, air intake location, air discharge location, air discharge temperature and blower speed.
The programmer also performs self-diagnostic functions for the electric A/C-heater system. Diagnostic Trouble Code (DTC) can be retrieved using a Tech 1 scan tester.
BLOWER CONTROL MODULE
Blower speed is controlled by blower control module located behind right side of dash, near blower motor. This module processes signals from A/C-heater programmer to provide variable blower speed.
SENSOR INPUTS
The A/C-heater programmer monitors these sensor signals and uses the information to determine A/C-heater command signals.
Ambient Temperature Sensor
Sensor is located on center of lower radiator support. Sensor resistance decreases as ambient air temperature increases, and increases as ambient air temperature decreases.
In-Vehicle Temperature Sensor
Sensor is located behind center of dash, right of steering column. Resistance of this sensor varies with temperature.
Solar Sensors
There is a solar sensor on each side of defroster grille. As sunlight intensity increases, resistance of sensor decreases; as sunlight intensity decreases, resistance increases.
OFF Mode
Blower motor and A/C compressor are off. When vehicle is moving, air flows in through the A/C-heater module assembly and out through floor and windshield outlets. A/C-heater programmer operates the air mix valve, and attempts to match in-vehicle and selected temperatures. Air can be warmed but not cooled since compressor is not running.
MAX A/C Upper Mode
In this mode, set temperature is at 60°F (16°C). If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). A/C-heater programmer closes defroster door, places air inlet door in recirculated air position, and positions A/C door to allow airflow through A/C vents. Blower draws inside air into system and then forces is out through instrument panel outlets. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
NORM A/C Upper Mode
NORM A/C can be accessed by A/C-heater programmer when operating in AUTO mode. If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). Programmer positions air inlet door so outside air is pulled into system by blower. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
BI-LEVEL Mode
If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). Programmer closes defroster door, places air inlet door in recirculated air position, and positions A/C door to allow airflow through A/C vents and floor outlets. Blower pulls outside air into system and forces it out through floor and dash outlets. Programmer determines proper air discharge temperature, and positions air mix door accordingly.
LOWER Mode
The A/C-heater programmer closes defroster door, and positions the air inlet door in recirculated air position. Programmer positions A/C door so air is discharged through heater vents. Programmer determines proper air discharge temperature, and positions air mix door accordingly.
DEFOG Mode
If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). Blower pulls outside air into system and forces it out through floor and windshield outlets. Programmer determines proper air discharge temperature, and positions the air mix door accordingly.
DEFROST Mode
Blower motor is turned on and blower speed can be manually adjusted using fan speed switch.If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). Programmer opens defroster door, and positions air inlet door to allow blower to draw outside air. A/C door is positioned to allow some air discharge through windshield vents. Programmer determines proper air discharge temperature, and positions air mix door accordingly.
AUTO Mode
In this mode, blower is turned on and blower speed is automatically controlled by A/C-heater programmer. Automatic blower fan speed can be overridden by depressing or turning fan speed switch. A/C-heater programmer evaluates information supplied by A/C-heater control and its network of sensors, then determines whether A/C, BI-LEVEL, DEFOG or HEAT mode is required. Programmer will then energize appropriate actuator(s) to enter this mode. Information supplied to programmer also determines whether outside air is drawn into system (NORM A/C mode) or inside air is recirculated (MAX A/C mode).
RECIRC Mode
When RECIRC mode is selected, programmer positions air inlet door in recirculated air position. RECIRC mode is available in UPPER, LOWER, and BI-LEVEL modes. RECIRC mode is not available during DEFROST mode. RECIRC mode times out (shuts off) after approximately 10 minutes. Selecting any other manual mode or turning ignition off cancels RECIRC mode.
DUAL ZONE Mode
When dual zone mode is selected, pressing PASS button or adjusting temperature on passenger control head, programmer operates driver and passenger air mix valves independently. If passenger temperature control knob is requesting a warmer or cooler temperature on that side of vehicle, programmer positions passenger air mix valve to increase or decrease passenger side discharge temperature.
In this mode, blower motor and A/C compressor will not run. Temperature control circuit is still activated so A/C-heater programmer can operate air mix door and attempt to match in-vehicle and selected temperatures. Since compressor is not running, system can be warmed but not cooled.
In this mode, blower motor is turned on and blower speed is automatically controlled by A/C-heater programmer. Operator can override automatic blower control by depressing fan speed switch. Programmer uses information supplied by A/C-heater control panel and its network of sensors to determine appropriate operation mode (FLOOR/WINDSHIELD, MID/FLOOR, MID or FLOOR). Programmer determines whether fresh air is drawn into system or inside air is recirculated.
FLOOR/WINDSHIELD Mode
This mode can be accessed by A/C-heater programmer when operating in AUTO mode. If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). A/C-heater programmer closes defroster door, places air inlet door in recirculated air position, and positions A/C door to allow air discharge through A/C vents and floor outlets. Blower draws outside air into system and forces it out through floor and windshield outlets. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
MID/FLOOR Mode
This mode can be accessed by A/C-heater programmer when operating in AUTO mode. If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). A/C-heater programmer closes defroster door, places air inlet door in recirculated air position, and positions A/C door to allow air discharge through A/C vents and floor outlets. Blower draws outside air into system and forces it out through floor and instrument panel outlets. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
MID Mode
This mode can be accessed by A/C-heater programmer when operating in AUTO mode. If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). A/C-heater programmer closes defroster door, and positions air inlet door to allow outside air to be drawn into system. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
FLOOR Mode
This mode can be accessed by A/C-heater programmer when operating in AUTO mode. A/C-heater programmer closes defroster door, places air inlet door in recirculated air position, and places A/C door to allow air discharge through heater vents. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
In this mode, blower is turned on and can be manually adjusted using fan speed switch. If ambient temperature is greater than 43°F (6°C), compressor will engage to keep evaporator core temperature at about 33°F (1°C). Programmer opens defroster door, and positions air inlet door to allow blower to draw in outside air. A/C door is positioned to allow some air discharge through windshield vents. The A/C-heater programmer determines proper air discharge temperature, and positions air mix door accordingly.
When RECIRC mode is selected, programmer positions air inlet door in recirculated air position. RECIRC mode is available in FLOOR/WINDSHIELD, MID/FLOOR, MID, and FLOOR modes. RECIRC mode is not available during DEFROST mode. RECIRC mode times out (shuts off) after approximately 10 minutes. Selecting any other manual mode or turning ignition off cancels RECIRC mode.
When dual zone mode is selected, pressing PASS button or adjusting temperature on passenger control head, programmer operates driver and passenger air mix valves independently. If passenger temperature control knob is requesting a warmer or cooler temperature on that side of vehicle, programmer positions passenger air mix valve to increase or decrease passenger side discharge temperature.
DUAL ZONE A/C SYSTEM CHECK (AURORA)
The A/C system check is an organized approach for locating a problem caused by automatic A/C system electronics. Understanding this diagnostic chart and using it correctly will reduce diagnostic time and prevent unnecessary replacement of parts. Please review information on how to use self-diagnostics. See SELF-DIAGNOSTICS.
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Scheme 11
DUAL ZONE A/C SYSTEM CHECK (RIVIERA)
The A/C system check is an organized approach for locating a problem caused by automatic A/C system electronics. Understanding this diagnostic chart and using it correctly will reduce diagnostic time and prevent unnecessary replacement of parts. Please review information on how to use self-diagnostics. See SELF-DIAGNOSTICS.
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A/C SYSTEM PERFORMANCE
- Park vehicle in shaded area. Ventilate interior. Vent exhaust. Install gauge set. Measure and record ambient temperature and relative humidity. Close doors and windows. Set controls to AUTO, select maximum blower speed, and set temperature control to coldest value. Insert thermometer into center outlet.
- Set transmission in Park or Neutral. Start and idle engine for 10 minutes. Record outlet temperature, and high side and low side pressures. Turn engine off. Compare readings with specifications. See A/C PERFORMANCE SPECIFICATIONS table.
| Ambient Temp. °F (°C) | Relative Humidity Greater Than | Outlet Temp. °F (°C) | Low Side psi (kg/cm 2 ) | High Side psi (kg/cm 2 ) |
|---|---|---|---|---|
| 70 (21) | 50% | 52-57 (11-14) | 25-30 (1.8-2.1) | 165-205 (11.6-14.4) |
| 80 (27) | 50% | 56-62 (13-17) | 35-43 (2.5-3.0) | 190-240 (13.3-16.9) |
| 90 (32) | 40% | 61-67 (16-19) | 40-48 (2.8-3.4) | 210-260 (14.8-18.3) |
| 100 (38) | 20% | 63-69 (17-21) | 44-52 (3.1-3.7) | 230-280 (16.2-19.7) |
| 110 (38) | 20% | 64-70 (18-21) | 46-54 (3.2-3.8) | 260-310 (18.3-21.8) |
A/C PERFORMANCE SPECIFICATIONS - RIVIERA
| Ambient Temp. °F (°C) | Relative Humidity Greater Than | Outlet Temp. °F (°C) | Low Side psi (kg/cm 2 ) | High Side psi (kg/cm 2 ) |
|---|---|---|---|---|
| 60-70 (16-21) | 40% | 39-49 (4-9) | 27-35 (1.9-2.5) | 155-200 (10.9-14.1) |
| 80 (27) | 40% | 47-56 (8-13) | 37-43 (2.6-3.0) | 180-240 (12.6-16.9) |
| 90 (32) | 40% | 53-63 (12-17) | 44-50 (3.1-3.5) | 210-270 (14.8-19.0) |
| 100 (38) | 40% | 60-70 (16-21) | 52-60 (3.7-4.2) | 250-310 (17.6-21.8) |
| 110 (38) | 40% | 70-80 (21-27) | 60-70 (4.2-4.9) | 290-360 (20.7-25.3) |
A/C PERFORMANCE SPECIFICATIONS - RIVIERA
Note. If A/C-heater programmer has been replaced, actuators need to be recalibrated for proper travel. To recalibrate actuators and programmer, cycle ignition switch to ON position for 3 minutes.
ACTUATORS
Note. If an actuator has been replaced, actuator need to be recalibrated for proper travel. To recalibrate actuator, cycle ignition switch to ON position for 3 minutes.