THEORY OF OPERATION
The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. There are currently three types of switches used depending on the configuration of the system. Push button momentary switches which are normally open or in the Off position. Multifunction or rotary switches which have several distinct positions and potentiometers which are a rotary variable resistor that is used for a more precise control. An active Diagnostic Trouble Code (DTC) indicates that either a control switch or potentiometer is stuck in an On position or out of a calibrated range. A stored DTC indicates that control switch or potentiometer was stuck On or out of calibration but has since returned to its normal state. For further information. Refer to CONTROL, A/C AND HEATER, DESCRIPTION .
The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. There are currently three types of switches used depending on the configuration of the system. Push button momentary switches which are normally open or in the Off position. Multifunction or rotary switches which have several distinct positions and potentiometers which are a rotary variable resistor that is used for a more precise control. An active Diagnostic Trouble Code (DTC) indicates that either a control switch or potentiometer is stuck in an On position or out of a calibrated range. A stored DTC indicates that control switch or potentiometer was stuck On or out of calibration but has since returned to its normal state. For further information. Refer to CONTROL, A/C AND HEATER, DESCRIPTION .
The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. There are currently three types of switches used depending on the configuration of the system. Push button momentary switches which are normally open or in the Off position. Multifunction or rotary switches which have several distinct positions and potentiometers which are a rotary variable resistor that is used for a more precise control. An active Diagnostic Trouble Code (DTC) indicates that either a control switch or potentiometer is stuck in an On position or out of a calibrated range. A stored DTC indicates that control switch or potentiometer was stuck On or out of calibration but has since returned to its normal state. For further information. Refer to CONTROL, A/C AND HEATER, DESCRIPTION .
A Blower Motor Power Module allows the microprocessor-based A/C Heater Control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming. The ATC blower motor control system uses a Pulse Width Modulated (PWM) circuit strategy. PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.
A Blower Motor Power Module allows the microprocessor-based A/C Heater Control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming. The ATC blower motor control system uses a Pulse Width Modulated (PWM) circuit strategy. PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.
A Blower Motor Power Module allows the microprocessor-based A/C Heater Control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming. The ATC blower motor control system uses a Pulse Width Modulated (PWM) circuit strategy. PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.
A Blower Motor Power Module allows the microprocessor-based A/C Heater Control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming. The ATC blower motor control system uses a Pulse Width Modulated (PWM) circuit strategy. PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.
The Evaporator Temperature Sensor is a variable resistor that changes in conjunction with temperature, or otherwise known as a thermistor. The Evaporator Temperature Sensor is located in the HVAC housing downstream of the A/C evaporator. The A/C Heater Module monitors the evaporator temperature by monitoring the voltage change of the Evaporator Temperature Sensor Signal circuit. If the monitored voltage drops below or rises above a predetermined voltage, a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, EVAPORATOR TEMPERATURE, OPERATION .
The Evaporator Temperature Sensor is a variable resistor that changes in conjunction with temperature, or otherwise known as a thermistor. The Evaporator Temperature Sensor is located in the HVAC housing downstream of the A/C evaporator. The A/C Heater Module monitors the evaporator temperature by monitoring the voltage change of the Evaporator Temperature Sensor Signal circuit. If the monitored voltage drops below or rises above a predetermined voltage, a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, EVAPORATOR TEMPERATURE, OPERATION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
The A/C Heater Controller has software to enable it to perform an A/C Cool Down Test by a command using a scan tool. This test checks for evaporator temperature drop over a predetermined time. If the test fails, this DTC will set. However, certain test conditions are required to perform this test. Failure to run this test within those parameters can result in failure of the test.
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. An active Diagnostic trouble Code (DTC) indicates that a sensor is out of range. A stored DTC indicates that the sensor was out of range but is currently within range.
The In-Car Temperature Sensor uses a temperature thermistor which changes in its resistive value with differences in air temperature of the interior cabin. Air is drawn from the passenger compartment by an aspirator (small fan driven by a 12-volt electric motor) which circulates air over the temperature thermistor. The A/C Heater Module receives the resistance value over a two wire circuit that is used to calculate the temperature and make any adjustments to maintain the optimum passenger compartment comfort. The In-Car Temperature Sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. An active Diagnostic trouble Code (DTC) indicates that a sensor is out of range. A stored DTC indicates that the sensor was out of range but is currently within range.
The In-Car Temperature Sensor uses a temperature thermistor which changes in its resistive value with differences in air temperature of the interior cabin. Air is drawn from the passenger compartment by an aspirator (small fan driven by a 12-volt electric motor) which circulates air over the temperature thermistor. The A/C Heater Module receives the resistance value over a two wire circuit that is used to calculate the temperature and make any adjustments to maintain the optimum passenger compartment comfort. The In-Car Temperature Sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
B11C2-92-FRONT MODE DOOR 1 CONTROL - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to ACTUATOR, MODE DOOR, OPERATION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to ACTUATOR, MODE DOOR, OPERATION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
B11C8-92-RIGHT TEMPERATURE DOOR CONTROL - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
B11CB-92-MAIN/LEFT TEMPERATURE DOOR CONTROL - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present. For further information. Refer to DESCRIPTION .
The Evaporator Temperature Sensor is a variable resistor that changes in conjunction with temperature, or otherwise known as a thermistor. The Evaporator Temperature Sensor is located in the HVAC housing downstream of the A/C evaporator. The A/C Heater Module monitors the evaporator temperature by monitoring the voltage change of the Evaporator Temperature Sensor Signal circuit. If the monitored voltage drops below or rises above a predetermined voltage, a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, EVAPORATOR TEMPERATURE, OPERATION .
B11D9-92-BLOWER SPEED KNOB REQUEST INPUT - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. There are currently three types of switches used depending on the configuration of the system. Push button momentary switches which are normally open or in the Off position. Multifunction or rotary switches which have several distinct positions and potentiometers which are a rotary variable resistor that is used for a more precise control. An active Diagnostic Trouble Code (DTC) indicates that either a control switch or potentiometer is stuck in an On position or out of a calibrated range. A stored DTC indicates that control switch or potentiometer was stuck On or out of calibration but has since returned to its normal state. For further information. Refer to CONTROL, A/C AND HEATER, DESCRIPTION .
B11DB-92- MODE SWITCH REQUEST INPUT - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
B11E9-92-LEFT TEMPERATURE KNOB REQUEST INPUT - PERFORMANCE OR INCORRECT OPERATION
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .
The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. There are currently three types of switches used depending on the configuration of the system. Push button momentary switches which are normally open or in the Off position. Multifunction or rotary switches which have several distinct positions and potentiometers which are a rotary variable resistor that is used for a more precise control. An active Diagnostic Trouble Code (DTC) indicates that either a control switch or potentiometer is stuck in an On position or out of a calibrated range. A stored DTC indicates that control switch or potentiometer was stuck On or out of calibration but has since returned to its normal state. For further information. Refer to CONTROL, A/C AND HEATER, DESCRIPTION .
After the initial installation of the A/C Heater Control, the controller is calibrated to each individual blend/mode door actuator. The actuators are connected to the A/C Heater Control by a dedicated five-wire sensor and control circuits. The actuator can move the blend/mode-air doors in two directions. When the A/C Heater Control pulls the voltage on one side of the control circuit high and the other low, the door actuator will move in one direction. When the A/C Heater Control reverses the polarity of the voltage to the motor, the door actuator moves in the opposite direction. Once the A/C Heater Control makes the voltage to both control circuits high or low, the door actuator will stop its movement and stay in that position. The blend/mode door actuator contains a three wire potentiometer, which the A/C Heater Control uses to monitor the relative position of the blend/mode air doors. The A/C Heater Control learns the blend-air door stop positions during the calibration procedure.
After the initial installation of the A/C Heater Control, the controller is calibrated to each individual blend/mode door actuator. The actuators are connected to the A/C Heater Control by a dedicated five-wire sensor and control circuits. The actuator can move the blend/mode-air doors in two directions. When the A/C Heater Control pulls the voltage on one side of the control circuit high and the other low, the door actuator will move in one direction. When the A/C Heater Control reverses the polarity of the voltage to the motor, the door actuator moves in the opposite direction. Once the A/C Heater Control makes the voltage to both control circuits high or low, the door actuator will stop its movement and stay in that position. The blend/mode door actuator contains a three wire potentiometer, which the A/C Heater Control uses to monitor the relative position of the blend/mode air doors. The A/C Heater Control learns the blend-air door stop positions during the calibration procedure.
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information. Refer to SENSOR, SUN, OPERATION .
The A/C Heater Module constantly monitors battery and ignition voltage as well as battery voltage derived from BUS communication to ensure proper operation. If the voltage to the controller is out of range, it could cause damage to the controller or its respective components. If the voltage of either circuit drops below or rises above a predetermined calibration a Diagnostic Trouble Code (DTC) will set.
The A/C Heater Module constantly monitors battery and ignition voltage as well as battery voltage derived from BUS communication to ensure proper operation. If the voltage to the controller is out of range, it could cause damage to the controller or its respective components. If the voltage of either circuit drops below or rises above a predetermined calibration a Diagnostic Trouble Code (DTC) will set.
The A/C Heater Module checks for vehicle configuration using communication over the BUS. If the stored configuration does not match the configuration stored in the controller this DTC will set.
See also:
• DTC INDEX
• STANDARD PROCEDURE