SsangYong Korando III (2010 year). Manual - part 576

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(6) A/C control

The air conditioner is operated at the defroster mode and MAX air conditioner mode and when the A/C 

switch is turned to "ON" position. It is controlled by the A/C compressor of the engine ECU according to 

the signal from the heater and A/C control assembly. The driver can see that the A/C has been activated 

when an indicator lamps at the A/C switch and MAX A/C switch comes on. If the intake sensor detects 

the freezing of the evaporator core, it stops the air conditioner by turning off the compressor.

MAX A/C control 

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This is designed for increasing driver comfort. When the switch is pressed, the air conditioner is 

operated and vent and recirculation modes are selected automatically. The discharge temperature and 

fan speed are regulated depending on the driver's choice. 

A/C switch

MAX A/C control switch

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6810-00

5. PTC HEATER OPERATION PROCESS

1) PTC Heater Input/Output Factors

The engine ECU controls the PTC (Positive Temperature Coefficient) heater system by adjusting the 

power supplied to the PTC system according to the two measured temperature values from the engine 

coolant temperature sensor and HFM sensor. This system is mounted to the heater air outlet in the air 

condition system module and heats the air which flows to the passenger room. Since the PTC system is 

heated by the electrical power, the electric load and alternator capacity is greater than the conventional 

one. The PTC is not operated when a) the engine is cranking, b) the battery voltage is below 11 V, c) the 

glow plug is being preheated.

The ceramic PTC features that the resistance rises quickly in a certain temperature range. The PTC 

heater has 3 circuits with power of 330 W. While only 1 circuit in the PTC heater is connected during 

PTC1 operation, 2 circuits are connected during PTC2 or PTC3 operation.
The PTC heater operates as follows: temperature rises above specified level→resistance 
increases→current decreases→calorific value decreases→temperature drops→resistance 
increases→current increases→temperature rises.

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2) Control Condition For PTC Heater

Operation

Operating condition

PTC heater status

HI mode operation
(PTC2, 3)

PTC heater operates in 
"HIGH" mode if operating 
conditions are met

LO mode operation 
(PTC1)

PTC heater operates in 
"LOW" mode if operating 
conditions are met

Conditions for 
deactivating

Air conditioner blower switch OFF
When the ambient temperature sensor is 
faulty (short or open circuit in the wiring)
Engine is cranking
Battery voltage is 11 V or less
Glow plug is being preheated (Glow indicator 
comes on)

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Coolant temperature < 15℃ 

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Coolant temperature 15℃ ≤ 65℃ and 
intake temperature ≤ -10℃
Coolant temperature 15℃ < 65 ~ 60℃ and 
intake temperature < -10℃ ~ 0℃
Coolant temperature 15℃ ≤ 65℃ and 
intake temperature ≤ 0℃ ~ 5℃

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Conditions for PTC heater "LOW" operation mode (2nd step)

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