Chery A series. Manual — part 117

The 28-socket connector of the wiring harness of combination instrument

The function of each socket is described in the table below:

Socket Function Socket

Function

1 No

connected 16

Connecting to the terminal D+ of

generator

2

Connecting to the water warning

switch of water tank

17

Air bag warning signal

3

Terminal 31# (ground)

18

Door light

4

TX1 speed signal of Hall Sensor

19

Seat belt warning lamp

5

Terminal 31#

20

Engine malfunction warning lamp

6

21

Connecting to the fuel meter sensor

7

22

Left-turn signal lamp

8

23

Water temperature signal of the ECU

9

Oil pressure warning switch

(30kpa)

24

Right-turn signal lamp

10 The

ECU

A20RPM 25

Power supply terminal for high beam

indicator lamp

11

Terminal 30#, power supply for

clock and multi-function display

26

Warning switch for brake oil level;

indicator lamp switch for hand brake

12

Terminal 58b#, power supply for

instrument panel illumination

27 Speedometer

sensor

13

Terminal 15#

28

Night illumination

14

ABS warning lamp

15 Diagnostic

wire

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1. SPEED ODOMETER

The Chery sedan A15LHD employs the cross coil type speedometer to indicate the driving
speed and accumulated road mileage, as well as equipped with digital odometer. The section
for measuring car speed employs a magnetic type of structure, while the section for recording
mileage is controlled by multifunction liquid crystal display.

See figure (Illustration-2)

Speedometer (Illustration-2)

The indicator needle is located at the scale zero when the speedometer is not in use. When the
car is driving, the transmission gear in the gearbox is activating and cutting the magnetic flux
of the permanent-magnet of the Hall Speed Sensor, so that the latter will produce pulse
signals to the cross coil type Speed Odometer to drive the indicator needle of speedometer,
and meanwhile it will also provide the same signal to the mileage-recording multifunction
liquid crystal display to control the mileage counting.

2. WATER TEMPERATURE METER

Water temperature meter

The Chery sedan A15LHD employs the water temperature meter equipped with cross coil
type indicator needle. See figure (Illustration-3)—the water temperature meter is located at
left.

Water temperature meter (Illustration-3)

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The pointer head of the cross coil meter is a kind of electromagnetic device. The coils are
round on the surface of its magnetic rotor in four directions, with an included angle of 90º
between the two adjacent coils. The strength of the current passing through the coils is
depended on the resistance of the sensor, so that the magnetic flux densities produced by the
coils in four directions are varied correspondingly, which subsequently activates the rotation
of the magnetic rotor and the movement of indicator needle.

3. FUNCTION AND PREINCIPLE OF WATER TEMPERATURE SENSOR

The water temperature sensor of Chery sedan A15 LHD employs the thermo-sensitive
resistance, which is shown in the figure above:

The coolant temperature sensor is used to inspect working temperature of the engine; the
ECM will provide the best control program for the engine according to different temperature
environment;

Composition and working principle: The sensor is a thermo-sensitive resistance of negative
temperature coefficient (NTC). Its resistance will decrease as the coolant temperature
increases, but not linearly related. This thermo-sensitive resistance of negative temperature
coefficient is loaded into a copper heat-conducted sleeve. The ECU converts the changes of
value of the thermo-sensitive resistance into variable voltages supplying the ECU via a
divider circuit so as to monitor the changes of the water temperature. (ECU’s internal
structure)

Pin: the sensor has 3 interchangeable pins totally.

1 Coolant temperature sensor signal (ECU39#)

2 Sensor signal ground (ECU35#)

3 Another wire is used to connect the water temperature signal of the instrument.

Installation: the coolant temperature sensor is mounted on the sub-loop passage of the coolant
behind the engine.

Notes on installation:

M

aximum tightening torque is 15Nm.

4. PRODUCT CHARACTERISTICS

Working voltage: 5V DC

Working temperature: -40 ~ 135

o

C

Figure of coolant temperature sensor

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The thermo-sensitive resistance is made of a kind of semiconducting material with negative
temperature coefficient, where its resistance will sharply decrease as the temperature
increases.

5. FUEL METER

The operation of the fuel meter is basically the same as the water temperature meter. It is also
the cross coil type of indicator needle meter. See figure below (Illustration-5)—the fuel meter
is located at right of the figure.

Fuel meter (Illustration-5)

When the float is moving along with the fuel level in the fuel tank, the sliding contact linked
with the float staff will respond accordingly so as to change the value of the thick-film
resistance. When the fuel tank is full, the value of the thick-film resistance will be the
minimum and the current of the cross coil will be the maximum. The indicator needle of the
fuel meter points at the maximum scale F. On the contrary, when the fuel in the tank is
exhausted, the value of thick-film resistance will be the maximum, and the indicator needle
deflexion value of the fuel meter points being the minimum scale E.

The relationship between fuel quantity and resistance is indicated in the table below.

The relationship between fuel quantity and resistance

Float position

Capacity (L)

Resistance (Ω)

Empty

0

283

Half full

30

89

Full 55 36

FAULT DIAGNOSIS AND TROUBLESHOOTING

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