Air Conditioning System: Overview Hyundai Accent III

Scheme 1

1. R-134a liquid refrigerant is highly volatile. A drop on the skin of your hand could result in localized frostbite. When handling the refrigerant, be sure to wear gloves.
2. It is standard practice to wear goggles or glasses to protect your eyes, and gloves to protect your hands. If the refrigerant splashes into your eyes, wash them with clean water immediately.
3. The R-134a container is highly pressurized. Never leave it in a hot place, and check that the storage temperature is below 52 °C (126 °F)
4. An electronic leak detector should be used to check the system for refrigerant leakage. Bear in mind that the R-134a, upon coming into contact with flame, produces phosgene, a highly toxic gas.
5. Use only recommended the lubricant for R-134a systems. If lubricants other than the recommended one used, system failure may occur.
6. PAG lubricant absorbs moisture from the atmosphere at a rapid rate, therefore the following precautions must be observed: When removing refrigerant components from a vehicle, cap immediately the components to prevent from the entry of moisture. When installing refrigerant components to a vehicle, do not remove the cap until just before connecting the components. Complete the connection of all refrigerant tubes and hoses without delay to prevent the A/C system from taking on moisture. Use the recommended lubricant from a sealed container only.
7. If an accidental discharge in the system occurs, ventilate the work area before resuming service.

Oil Return Operation

There is close affinity between the oil and the refrigerant.

During normal operation, part of the oil recirculates with the refrigerant in the system.

When checking the amount of oil in the system, or replacing any component of the system, the compressor must be run in advance for oil return operation. The procedure is as follows

1. Open all the doors and the engine hood.
2. Start the engine and air conditioning switch to "ON" and set the blower motor control knob at its highest position.
3. Run the compressor for more than 20 minutes between 800 and 1,000 RPM in order to operate the system.
4. Stop the engine.

Description

The A/C pressure transducer provides a voltage signal to the ECM/PCM that is used for compressor clutch and cooling/condenser fan control.

Scheme 2

1. Measure the pressure of high pressure line by measuring voltage output between No. 1 and No. 2 terminals
2. Inspect the voltage value whether it is sufficient to be regular value or not. Voltage = 0.00878835 * Pressure + 0.037081095 [PSIA]
3. If the measured voltage value is not specification, replace the A/C pressure transducer.

Scheme 3

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Scheme 6

1. Disconnect the negative (-) battery terminal.
2. Recover the refrigerant with a recovery/charging station. (Refer to «REFRIGERANT RECOVERY»(ref-380330-S30406824212010121800000) )
3. Remove the discharge line (A) & suction line (B) for wide space. TORQUE: 8 ~ 12 N.m (0.8 ~ 1.2 kgf.m, 5.8 ~ 8.7 lbf.ft)
4. Disconnect A/C pressure transducer connector (3P) (A).
5. Remove the bolt, then disconnect the liquid/suction pipe (A) from the expansion valve.
6. Remove the A/C pressure transducer (B) while holding on to the fitting block (A). CAUTION: Take care that liquid & suction pipe are not bent.
7. Installation is the reverse order of removal. TORQUE: 10 ~ 12 N.m (1.0 ~ 1.2 kgf.m, 7.4 ~ 8.8 lbf.ft)

Scheme 7

The evaporator temperature sensor will detect the evaporator core temperature and interrupt compressor relay power in order to prevent evaporator freezing by excessive cooling.

It is a negative type thermistor whose resistance is inversely proportional to temperature.

Scheme 8

1. Ignition "ON"
2. A/C switch "ON".
3. Using the multi-tester, Measure resistance between terminal "1" and "2" of evaporator temperature sensor. [Specification] EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATION Evaporator core temperature [°C (°F)] Resistance [kohms] -2 (28.4) 30.16 0 (32.0) 27.62 ± 1% 2 (35.6) 25.32 4 (39.2) 23.24 6 (42.8) 21.35
4. If the measured resistance is not specification, substitute with a known-good evaporator temperature sensor and check for proper operation.
5. If the problem is corrected, replace the evaporator temperature sensor.

Scheme 9

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Scheme 11

1. Disconnect the negative (-) battery terminal.
2. Remove the passenger's crash pad lower cover (C).
3. Disconnect the evaporator sensor connector (A).
4. Remove the evaporator temperature sensor (B) by pulling it after rotating 90° in a counterclockwise direction. CAUTION: Take care that evaporator core pins are not bent.
5. Installation is the reverse order of removal.

Scheme 12

Scheme 13

1. In-car air temperature sensor is located at the center facia lower panel.
2. The sensor contains a thermistor which measures the temperature of the inside. The signal decided by the resistance value which changes in accordance with perceived inside temperature, is delivered to heater control unit and according to this signal the control unit regulates in-car temperature to intended value.

1. The photo sensor (A) is located at the center of defrost nozzle.
2. The photo sensor contains a photovoltaic (sensitive to sunlight) diode. The solar radiation received by its light receiving portion, generates an electromotive force in proportion to the amount of radiation received which is transferred to the automatic temperature control module so that the solar radiation compensation will be performed.

Scheme 14

1. Ignition "ON"
2. Using the scan tool.
3. Emit intensive light toward photo sensor using a lamp, and check the output voltage change.
4. The voltage will rise with higher intensive light and reduce with lower intensive light.

Scheme 15

1. Disconnect the negative (-) battery terminal.
2. With the (-) driver, remove the photo sensor (B) from the center of defrost nozzle (A).
3. Install in the reverse order of removal.

Scheme 16

Scheme 17

1. Water temperature sensor is located at the heater unit.
2. It detects coolant temperature. Its signal is used for cold engine lockout control. When the driver operates the heater before the engine is warmed up, the signal from sensor causes the heater control unit to reduce blower motor speed until coolant temperature reaches the threshold value.

Scheme 18

1. Ignition "ON"
2. Using the multi-tester, Measure resistance between terminal "1" and "2" of water temperature sensor. [Specification] TEMPERATURE, RESISTANCE AND VOLTAGE SPECIFICATION Coolant temperature [°C (°F)] Resistance (kohms) Voltage (V) -10 (14) 55.85 ± 3% 4.24 ± 3% 0 (32) 32.91 ± 3% 3.83 ± 3% 10 (50) 19.99 ± 3% 3.33 ± 3% 20 (68) 12.51 ± 3% 2.78 ± 3% 30 (86) 8.047 ± 3% 2.23 ± 3% 40 (104) 5.311 ± 3% 1.73 ± 3% 50 (122) 3.588 ± 3% 1.32 ± 3% 60 (140) 2.476 ± 3% 0.99 ± 3% 70 (158) 1.742 ±3% 0.74 ± 3% 80 (176) 1.246 ± 3% 0.55 ± 3%
3. If the measured resistance is not specification, substitute with a known-good water temperature sensor and check for proper operation.
4. If the problem is corrected, replace the water temperature sensor. NOTE: Negative type thermistor that resistance will rise with lower temperature, and reduce with higher temperature.

Scheme 19

Scheme 20

Scheme 21

1. Disconnect the negative (-) battery terminal.
2. Remove the passenger's crash pad lower cover (C).
3. Disconnect the water temperature sensor connector (B).
4. Pull the water temperature sensor (E) out at the heater unit with the stopper (D).
5. Installation is the reverse order of removal. NOTE: Take care that wire of water temperature sensor is not to be damaged.

Scheme 22

1. The ambient temperature sensor is located at the front of the condenser and detects ambient air temperature. It is a negative type thermistor; resistance will increase with lower temperature, and decrease with higher temperatures.
2. The sensor output will be used for discharge temperature control, temperature regulation door control, blower motor level control, mix mode control and in-car humidity control. NOTE: If the ambient temperature is below 2.0 °C (35.6 °F), the A/C compressor will be stopped. The compressor will be operated by manual operating.

Scheme 23

1. Ignition "OFF"
2. Disconnect ambient temperature sensor.
3. Check the resistance of ambient temperature sensor between terminals 1 and 2 whether it is changed by changing of the ambient temperature. [Specification] TEMPERATURE AND RESISTANCE SPECIFICATIONS Ambient temperature [°C (°F)] Resistance between terminals 1 and 2 (kohms) -10 (14 164 ± 3% 0 (32) 97.5 ± 3% 10 (50) 59.6 ± 3% 20 (68) 37.5 ± 3%
4. If the measured resistance is not specification, substitute with a known-good ambient temperature sensor and check for proper operation.
5. If the problem is corrected, replace the ambient temperature sensor.

Scheme 24

1. Disconnect the negative (-) battery terminal.
2. Remove the front bumper. (Refer to «FRONT BUMPER»(ref-380306-S09484704672010121800000) )
3. Remove the ambient temperature sensor (A).
4. Installation is the reverse order of removal.

Scheme 25

1. A.Q.S is located at center support in front of the engine radiator, and detects hazardous elements in ambient air providing output signal to control.
2. It will detect sulfurous acid gas, carbon dioxide, carbon monoxide, hydrocarbon and allergen.

Scheme 26

1. Ignition "ON"
2. Using the scan tool.
3. Check the output voltage of AQS between terminals 2 and 3. [Specification] VOLTAGE SPECIFICATIONS Condition Output signal Fresh/recirculation Normal condition 4 ~ 5 V Fresh Hazardous gas detection 0 ~ 1 V Recirculation
4. AQS diagnosis and fail safe. Detect the open of signal for 7 seconds without choosing the AQS switch when IG on. If 2.5 V or more is detected for 3.5 seconds or more among 7 seconds, be judged the open of AQS signal. Operate as below fail safe function, while choosing AQS. Fail safe: Release the AQS (AQS cannot be selected), Fresh/recirculation maintains previous situation of AQS selection. NOTE: When IG is turned ON, AQS heats for 34 ± 5 seconds, it will output below 1.0 voltage during this time.

Scheme 27

1. Disconnect the negative (-) battery terminal.
2. Remove the front bumper (Refer to «FRONT BUMPER»(ref-380306-S09484704672010121800000) ).
3. Remove the AQS (B) after loosening the mounting bolts (A).
4. Installation is the reverse order of removal.