MTZ 952.2 - Combination Meter Diagnostics and Troubleshooting

Controls and Instrumentation
MTZ series 900
25
1.16. Combination Meter Diagnostics and
Troubleshooting
1. No backlight of the instrument scales
on setting the SA10 central light switch:
1. Check the presence of the power supply
voltage at the terminal “1” of the block “Х1”
(to the instrument backlight switch) and at
the terminal “9” (to the power supply unit “+
12 V”).
In case of absence of the voltage, eliminate
the open circuit. If the voltage is present:
2. Check the intactness of the backlight
lamps and replace them, if necessary.
2. The temperature indicator (1), Fig. 9,
operated jointly with the thermistor-type
temperature sensor BK1 (ДУТЖ-02М, re-
sistance range: 243…22.5 Ω).
2.1. The temperature indicator pointer
goes off-scale:
1. Breakage of the wire to the terminal “9” of
the block “Х1” (“+” 12 V of the SB);
2. Breakage of the wire to the terminal “2” of
the block “Х1” (“–” of the power supply);
3. If there is no breakage, the temperature
indicator is faulty.
2.2. The pointer of the temperature indi-
cator is set before the initial point of the
scale:
1. Breakage of the wire to the terminal “9” of
the block “Х1” (“+” 12 V of the SB);
2. Breakage of the wire to the terminal “8” of
the block “Х1” (to the temperature indicator
BK1);
3. Fault of the temperature sensor;
4. Fault of the temperature indicator.
3. Indicators of the oil pressure in the en-
gine (2) and air pressure in the pneumatic
system (3). They operate from the follow-
ing sensors:
Rheostat-type oil pressure (ВР1) (ДД-6М;
10…184 Ω) and rheostat-type oil pressure
(ВР2) (ДД-10-01М).
3.1. The indicator pointer is set before the
initial point of the scale:
1. Breakage of the wire to the terminal “2” of
the block “Х1” (“–” of the power supply);
2. Breakage of the wire to the terminal “9” of
the block “Х1” (“+” of the power supply);
3. If there is no breakage, the pressure indi-
cator is faulty.
Fig. 9.
IMPORTANT! To avoid errors in the tem-
perature indication, use the ДУТЖ – 02М
temperature sensors mentioned above.
3.2. The indicator pointer goes off-scale:
1. Breakage of the wires to the terminals “4”,
“5”, “7” of the block «Х1» or short circuit inside
the indicator;
2. The pressure indicator is faulty.
4. Fuel level indicator (4).
It operates with the float-type rheostat sensor
(BN1) installed in the fuel tank (ДУМП-21М
(320…0 Ω)).
NOTE! Should there be no fuel in the tank
when switching on the indicator; the indica-
tor pointer shall be at the initial point of the
scale. If the indicator is switched off or there
is a wire breakage, the indicator pointer
shall go off-scale.
4.1. The indicator pointer is before the initial
point of the scale:
1. Breakage of the wire to the terminal “9” of
the block “Х1” (to the terminal “+12V”);
2. Breakage of the wire to the terminal “3” of
the block “Х2” (to the fuel level sensor);
3. The fuel level sensor is faulty;
if there is no breakage and the sensor is in
good repair, replace the combination meter