Main malfunctions of control devices (VAZ-2109)

The temperature indicator arrow is constantly at the beginning of the scale

Causes of the malfunction and ways to eliminate it:

• the device sensor is faulty. Pre-warm the engine, turn on the ignition, disconnect the wire from the sensor (it is installed on the cylinder head) and touch the metal parts of the engine with the tip of this wire. If the pointer deviates, the sensor is faulty and must be replaced;
• the wires are damaged or their tips are oxidized. If the pointer does not move when the tip of the sensor wire is connected to the ground, remove the instrument cluster without disconnecting the wire blocks from it, turn on the ignition and connect the upper terminal of the temperature gauge, which is connected to plug 2 (see figure 132) white block of the instrument cluster. In this case, the deviation of the pointer will indicate damage to the green wires with a white stripe connecting the sensor to the pointer. Check the wires and their connections, replace damaged wires;
• the temperature gauge is faulty. If the pointer does not move when connected to the ground of the upper terminal of the gauge, then it is not working and must be replaced.

The temperature indicator arrow is constantly at the end of the scale

Causes of the malfunction and ways to eliminate it:

• the device sensor is damaged. Turn on the ignition and disconnect the wire from the sensor. If the device pointer returns to the beginning of the scale, the sensor is faulty and must be replaced;
• short circuit to ground of the green wires with a white stripe connecting the sensor to the indicator. If, when disconnecting the wire from the sensor, the indicator arrow does not return to the beginning of the scale, then you need to remove the instrument cluster, disconnect the wires from its white (right) block and connect plug 5 to ground (figure 132) of this block, and plug 12 with the "plus" of the battery. If the arrow deviates to the beginning of the scale, then the device is in good condition, and there is a short circuit to "ground" in the wires connecting it to the sensor. Inspect the wires, replace or insulate damaged ones;
• the temperature gauge is damaged. If the arrow does not return to the beginning of the scale during the check described above, the gauge is faulty and must be replaced.

The fuel gauge needle is constantly at the beginning of the scale

Causes of the malfunction and ways to eliminate it:

• the fuel gauge sensor is faulty. Fold the rear seat cushion forward, fold the floor mat and remove the hatch cover in the floor above the fuel gauge sensor. Turn on the ignition, disconnect the wiring block from the sensor and connect the tip of the pink wire in this block to the ground. If the instrument needle deviates, the sensor is damaged. Remove the sensor and inspect its parts. Check for a break in the flexible busbar or the sensor resistor winding and for reliable contact between the current collector and the resistor. Solder the broken busbar and, if necessary, bend the current collector to ensure reliable contact with the resistor. If there is a break in the resistor, replace the sensor;
• the wires connecting the sensor to the indicator are damaged, or their connections are oxidized. If the indicator needle does not move when connected to the ground of the pink wire tip, remove the instrument cluster without disconnecting the wire blocks from it, turn on the ignition and connect the lower terminal of the fuel level indicator, which is connected to plug 13 (see figure 132) white block of the instrument cluster. If the arrow deviates, the device is working properly, but the wires connecting it to the sensor are damaged. Check the wires and their connections, replace damaged wires;
• the fuel gauge is faulty. If the gauge needle does not move during the above check, it is faulty and must be replaced.

The fuel gauge needle is constantly at the end of the scale

Causes of the malfunction and ways to eliminate it:

• short circuit to ground in the indicator sensor. To check with the ignition on, disconnect the wiring harness from the sensor. If the pointer returns to the beginning of the scale, then there is indeed a short circuit to ground in the sensor. Remove the sensor and inspect it. Check whether the flexible busbar is shorted to the fuel intake tube. Eliminate the short circuit;
• short circuit to ground in wires (pink and pink with red stripe), connecting the sensor to the pointer. If, when disconnecting the wires from the sensor, the arrow does not return to the beginning of the scale, then remove the instrument cluster, disconnect the right (white) wiring block from it and connect plug 5 (figure 132) of the white block of the instrument cluster, and plug 12 with the "plus" of the battery. If the arrow deviates to the beginning of the scale, then there is a short circuit in the wires connecting the sensor to the indicator. Check the wires, eliminate the short circuit;
• the indicator is damaged. When performing the above check, the arrow does not move to the beginning of the scale. Replace the faulty fuel level indicator.

The fuel gauge needle moves in jumps and often drops to the beginning of the scale

The most likely causes are a weak contact of the sensor resistor with the current collector or a break in the sensor resistor winding. Remove the sensor and inspect it. Bend the current collector, replace the sensor if there is a break in the resistor winding.

The fuel reserve indicator light is constantly on

Causes of the malfunction and ways to eliminate it:

• short circuit of the flexible bus of the sensor with the fuel intake tube. With the ignition on, disconnect the wires from the fuel level indicator sensor. If the lamp goes out, there is a short circuit in the sensor. Remove it and eliminate the short circuit;
• short circuit to ground in the wires connecting the control lamp to the sensor. If the lamp does not go out when the wires are disconnected from the sensor, then you need to check the wires and eliminate the short circuit to ground.

The fuel reserve indicator light does not come on

Causes of the malfunction and ways to eliminate it:

• the sensor contacts are oxidized or do not close. With the ignition on, disconnect the wires from the sensor and connect the tip of the blue wire with the red stripe to the "ground". If the lamp lights up, remove the sensor, clean its contacts, bend the movable contact;
• the control lamp has burned out. If the lamp does not light when the tip of the blue wire with the red stripe is connected to the "ground", remove the instrument cluster and check the lamp. Replace the burned out lamp;
• the wires connecting the lamp to the sensor are damaged, or their tips are oxidized. If the lamp and sensor are in good condition, but the lamp does not light, then check the blue wires with a red stripe connecting the sensor to the control lamp. Replace damaged wires.

The speedometer does not work

Causes of the malfunction and ways to eliminate it:

• the nuts securing the flexible shaft on the speedometer or its drive have loosened. Remove the instrument cluster, check the tightness of the nuts, and tighten them if necessary;
• speedometer flexible shaft break. Replace damaged shaft;
• the speedometer mechanism is damaged. Contact a service station to check and, if necessary, replace the speedometer.

Speedometer Flexible Shaft Noise

Causes of the malfunction and ways to eliminate it:

• the flexible shaft shell is deformed. Inspect it; if there are dents, bends, etc. on it, replace the flexible shaft;
• the flexible shaft installation is performed with bending radii less than 100 mm. Check and, if necessary, correct the flexible shaft installation.

The parking brake indicator light does not come on

Causes of the malfunction and ways to eliminate it:

• the control lamp has burned out. Remove the instrument cluster and replace the lamp;
• oxidation of the contacts of the parking brake relay-breaker. Remove the relay-breaker cover (it is installed on the back of the instrument cluster), clean the contacts, eliminate the gap between them;
• the indicator lamp switch is faulty. Disconnect the wire from the switch installed under the parking brake lever, turn on the ignition and connect the wire tip to the "ground". If the lamp lights up, clean the switch contacts or replace it;
• the wires connecting the switch to the instrument cluster are damaged. If the lamp does not light during the previous check, then check the brown wires with a blue stripe connecting the switch to the instrument cluster. Replace damaged wires.

Parking brake indicator light does not flash (it's on constantly)

The reason is only a break in the winding of the relay-breaker. Use an ohmmeter or a test lamp to check whether the circuit between the plugs "-" and "+" of the relay-breaker is in good condition. If the circuit is faulty, replace the relay-breaker.