cb750 dual gauge oil temp and pressure

• 2022-05-23

The internal structure of oil pressure gauge and fuel gauge is the same, but there are only differences in dial identification and scale range. The signal sampling devices used by them: oil pressure sensing plug and fuel tank sensor, although they differ greatly in appearance, have the same electrical properties. When the signal is zero, the resistance is about 200L when the resistance is full scale, and the interior is sliding resistor. By controlling the grounding resistance, the magnetic field current of the secondary coil in the instrument is determined to turn the pointer to different angles. This feature provides us with a simple and practical fault judgment method.

After the ignition switch is turned on, the needle of the oil pressure gauge should move once in normal condition, and the needle of the fuel gauge should indicate the fuel level. If the needle of VL meter does not move, other instruments and alarm signal lights do not work, which reflects that the fault is on the power side including the ignition switch. If only instruments do not work, check the condition of the fuse F9: the fuse is intact, and check the connection of circuit wires; If the fuse is damaged, the "power transmission method" can be used to find the location of short-circuit fault. Other instruments work normally. If the meter needle does not move after turning on the power supply, check the connection of the meter socket.

If the measured voltage is normal, there is an internal fault and needs to be replaced. If there is an open circuit fault in the circuit of sensor, connecting wire and auxiliary coil in the instrument, the gauge needle will quickly turn to the high limit position after turning on the ignition switch. In this case, the "short circuit method" can be used to determine the fault location. The method is: Unplug the sensor wiring of the corresponding instrument and ground it reliably. If the gauge needle falls, it indicates that the fault is inside the sensor and there is no change, conduct grounding test on the relevant wires of the harness connector until the instrument socket is found, and ground the wiring terminal in the instrument socket. If the gauge needle still does not fall, the fault is inside.