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 4. Heater

Figure 5 Heater Door Control Diagram

The heater comprises the heater radiator (heat exchanger), the plastic case forming the air duct, connecting

rods adjusting different air ducts and the door. The two groups of combination doors in the heater case are

connected to the heating control mechanism by the cable. The first group is the two couple action doors

adjusting the air mix ratio that are located in the outlet and inlet each; the second group comprises 4 doors

controlling the air outlet vents, where the upper center one controls the front outlet vent, each of the upper

left and right sides controls a defogger outlet vent and lower foot outlet vent. Figure 5 shows the working

principle of temperature adjustment door. The d) , c) , e) , f) in the figure indicate the outlet air flow direction

as the result of the adjustment of the control knob in the heating control mechanism panel.

Hot Wind Location

Cold Wind Location

Linkage

Radiator Core

Radiator Core

Temperature Adjustment 
Door Working Principle

Foot Outlet

To Front Outlet

To Defroster

Radiator Core

To Front Outlet

Radiator Core

Foot Outlet

Foot Outlet

To Defroster

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Section 3  A/C controlling system

I. Introduction and Composition

In order to ensure the effective opeation of the A/C system in any operating condition, some advanced

electric control devices are used to protect the A/C system in adverse engine operating condition.

The electrical control part consists of: A/C switch, relay, evaporator temperature sensor, water temperature

sensor, pressure switch, ECU...etc.

A/C system circuit diagram is shown in Figure 6.

II. controlling system feature

(1) The condenser fan's power is 90W;

(2) The performance of the condenser fan is controlled by ECU, pressure switch;

(3) Cut off the electrical power of the A/C compressor clutch when the water temperature reaches 109°C;

(4) Connect blower switch 9 to rotate the blower motor 6 to ensure A/C normal operation. Connect A/C

switch 10 to output A/C request signal to ECU.

(5) After ECU receives the request signal and the one from the evaporator temperature sensor 17, if the

engine is at idle, ECU first increases the engine speed to 950 ± 50r/min, lest the A/C operation enhance

the load and lower the engine speed or result in engine off. And then the ECU can respond. If the engine

is in accelerating condition, ECU does not respond immediately either, and respond 5 seconds later after

the end of the accelerating condition. ECU send out a A/C control signal from pin 22 to relay 7, command

the relay to suction in. With the low pressure switch 11 closed, the compressor 12 starts to work when the

magnetic clutch suction on. The condenser relay holds in and condenser blower 13 rotates. When high

pressure switch 15 is closed, have the relay 7 hold in and the water tank fan 14 rotates. When the water

temperature sensor 16's temperature is higher than 109°C, ECU shut off the output signal of the pin 22

and A/C stops operation.

(6) When the Refrigeration system pressure is over 1.7MPa, radiator fan will rotato. Disconnect A/C

compressor Refrigeration system power supply when the pressure is over 2.6MPa or less than 0.25MPa;

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Figure 6 A/C System Electrical Appliance Diagram

III. Protecting Device

1. Low temperature protection

Evaporator temperature sensor, when the sensed temperature is lower than 3°C, the compressor clutch

is de-energized and stops operation.

2. High temperature protection

Water temperature sensor, when the sensed water temperature reaches 109°C, the compressor clutch is

de-energized and stops operation.

3. Low pressure protection

When pressure sensed by the pressure switch is lower than 0.25MPa, the compressor clutch is de-

energized and stops operation.

4. Voltage protection

When the pressure sensed by the pressure switch reaches 1.7MPa, radiator fan rotates.

5. High pressure protection

When the pressure sensed by the pressure switch reaches 2.6MPa, the compressor clutch is de-energized

and stops operation.

6. Normal pressure

When system pressure reaches 0.25MPa~2.4MPa, control the A/C idle speed.

                                                       

 Color of wire:

R-Red Bl-Blue Y-Yellow Lg-Light green Br-Brown B-Black P-Pink G-Green W-White Gr-Gray
1. Battery 2. Main Fuse Box 3. Alternator 4. Ignition Switch 5. Idle Rise Valve 6. Blower 7. Relay
8.  Blower Regulating Resistance 9. Blower Switch 10. A/C Switch 11. A/C Low Pressure Switch 
12. Compressor 13. Condensor Fan 14. Radiator Fan 15. A/C High Pressure Switch 
16. Water Temperature Sensor 17. Evaporator Temperature Sensor 18. Electronic Wind Door Actuator Switch 
19. Electronic Wind Door Actuator 20. Revolution Sensor 21. Engine ECU

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Section 4 Service Caution & Notice

I. Service Caution

Refrigerant Treatment

•

During the treatment, the operator shall be careful not to inhale A/C refrigerant or lubricant vapor. Long-

term exposure to the A/C environment will cause the operator's eye, nose and throat liable to stimulation.

In addition, based on the consideration on the environment influence, when discharging the HFC-134a

from the A/C system, we suggest using the recyclable and rechargeable devices. If sudden system fault

occurs, it is recommended to place the device on a ventilated place before starting service.

•

For HFC-134a service equipment, it is recommended not to perform the pressurization check or leakage

inspection. If these mixture combust, it may result in severe human injury or property loss.

•

Please be noticed not to let the refrigerant leak near the spark or other hot objects. If the refrigerant gas

contacts the spark or similar heat source (e.g. cigarette or heater), it may generate poisonous gas. The

refrigerant is extremely liable to leakage during the transportation. In this case, please eliminate or remove

the heat source mentioned above and keep good ventilation.

•

It is very dangerous to handle the liquid refrigerant. Only a drop of refrigerant can result in local frostbite

on skin if dropped on the skin of the operator. Therefore, it is specified that the operator shall always

wear glove and eye protection during the handling of the liquid refrigerant. If liquid refrigerant gets in

your eyes or on your skin, Wash the area with much cool water. Go immediately to hospital for professional

treatment.

Refrigerant Preservation

•

 Refrigerant preservation container is a high pressure resistant equipment. If it is put in hot treatment, the

explosion may arise, and the resulting metal fragments and the splashed liquid refrigerant will result in

severe human injury. It is recommended to preserve the refrigerant below 40°C.

II. Service Notice

Insufficient Refrigerant Handling

•

If the refrigerant is founded to be insufficient during the fault diagnosis, it is recommended not to add

refrigerant because of the following facts: the pressure readings indicated by different pressure gauge

are different, thus you will be unable to determine the exact amount of the refrigerant to be added, and

excessive or insufficient refrigerant may cause a series of chained negative effects such as damaged

refrigerant circulation parts or deteriorated refrigeration effect. Therefore, if the refrigerant is found to

be insufficient, it is recommended to drain the refrigerant from the refrigerant circulation pipeline and fill

specified amount of the refrigerant.

Compressor Oil Handling

•

For this type of vehicle, it is recommended to use SW-100 type compressor oil. Use of PAG compressor

oil other than the SW-100 type may cause the A/C compressor to be damaged.

•

During the operation, please be noticed not to splash the SW-100 type compressor oil onto the vehicle

surface. Therefore, if this happens, please wipe it off immediately, otherwise the compressor oil will

damage the paint on the vehicle surface.