Common faults of water temperature gauge:
Turn on the ignition switch, and the pointer of the water temperature gauge always means that it does not move above 100 ℃. When the water temperature changes, the pointer does not move with it; When the ignition switch is turned on and the pointer of the water temperature gauge moves to 40 ℃, the engine temperature rises, but the pointer does not move.
Cause of failure:
Open circuit of power line; The electric heating coil of the meter is disconnected; The electric heating coil of the water temperature sensor is disconnected, the wiring screw is loose, the header wire is disconnected, the internal short circuit, and the water temperature sensor is invalid; The water temperature gauge fails, and the wire from the water temperature gauge to the sensor is grounded.
Exclusion method:
1. Check the ammeter (the breaker contact must be closed), if the ammeter indicates 0 position. Indicates that a section of common circuit from the battery to the ignition switch power terminal is open; If the ammeter shows that the discharge is about 5 A, it means that the common circuit is powered on, and the circuit from the terminal of ignition switch II to the water temperature gauge and sensor is open. The fire test can be conducted by grounding the fire inlet terminal of the water temperature gauge.
2. Use the middle part of the screwdriver to close to the fire inlet terminal of the water temperature gauge, so that the tip of the screwdriver touches the metal part of the machine. If there is no spark, it means that a section of wiring from the ignition switch to the water temperature gauge is disconnected. If there is spark during the grounding fire test, use a screwdriver to ground the terminal of the water temperature sensor. If the pointer of the water temperature gauge quickly turns to 40 ℃, it indicates that the water temperature sensor is damaged.
3. The water temperature gauge pointer always refers to the fault at 40 ℃. The troubleshooting method is to close the ignition switch, and the water temperature gauge pointer quickly turns from the position above 100 ℃ to 40 ℃. After the engine temperature rises, the pointer of the water temperature gauge still points to 40 ℃, indicating that there is a fault in the circuit from the water temperature gauge to the water temperature sensor. The wiring of water temperature sensor can be removed for open circuit test. If the pointer of the water temperature gauge turns back to the position above 100 ℃, it indicates that the water temperature sensor is internally grounded.
