Chery QQ, Service Manual

Page: 415 / 635

Chery QQ Service Manual
The ECU makes the low speed relay operating after receiving the A/C switch closed
signal, then the fan begins to work. When the water temperature is higher than certain
degree, ECU will make the fan‘s high speed relay operating automatically, then the
high speed fan works.
The pressure switch in this circuit is fitted on the side of the high pressure loop (i.e.
drying bottle mouth) of the air conditioning cooling midum loop, its function is to
protect refrigeration loop when abnormal pressures occurs due to over-charged
refrigerant or gas leakage. Pressure switch signals are sent to the ECU that will stop
the compressor by disconnecting the air conditioner relay when the pressure switch
disconnects for some reasons.
The temperature sensor in this circuit is an electric one (thermistor), the resistance
value of which changes as temperature changes. So the thermistor connects or
disconnects the electric magnetic clutch, drive or stop the compressor by sensing air
temperature blew by air conditioner. Therefore it can control the interior temperature
and avoid frosting to make a constant temperature.
The ECU controls the compressor’s electric magnetic clutch and condensator fan
motor on basis of detecting the running condition for engine and signals from sensors.
ECU will connect air conditioner and condensator fan only when the following
conditions are met:
Engine rotate speed: 600-6000r/min
Engine cooling temperature:below 110
℃
Evaporator temperature:over 4
℃
Refrigerant pressure switch:on
AC switch and the air blower switch:on
Section 2 Safety Cautions for Air conditioning System
1. Do not deal with the refrigerant in closed place or colse to fire.
2. Be sure to take safety goggles.
3. Take good care of the refrigerant. Avoid the liquid refrigerant to splash into your
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