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freightliner tach and speedometer not working
Common fault causes are as follows: 1. The speedometer of the vehicle's instrument assembly may have a fault, causing the pointer of the speedometer to stop rotating. 2. The wheel speed sensor of the vehicle may have a fault, causing the meter to stop rotating. 3. The mileage sensor of the vehicle may have a fault, which causes the meter to stop rotating.
What happened when the speedometer stopped
There are two cases when the speedometer does not move. One is when it is 0, which generally means it is broken or short circuited; The other is to stay still at the highest point, which is what we often say when the meter breaks. You can reset it.
If it does not move at 0 and the mileage number does not move, it is very likely that there is a problem with the speed sensor, or there may be a problem with the circuit between the instrument and the sensor. It is a small problem to ask the factory for maintenance. First check whether the flexible shaft is disconnected, and then check whether the mileage increases when starting. If it is the tachometer does not move. There is no need to repair it, just replace it with a new one.
As long as the car starts, the gear in the tachometer will rotate. It will wear out after a long time. The gear in the watch is plastic, and the new one doesn't cost much.Tachometer It receives the pulse signal generated when the primary current in the ignition coil is interrupted, and converts this signal into a speed value that can be displayed.
The faster the engine speed, the more pulses generated by the ignition coil, and the greater the speed value displayed on the table. Generally, cars are electronic tachometers with pointer type and LCD digital display type. There are digital integrated circuits in the meters, which drive pointer movement or digital display after calculating the voltage pulse transmitted from the ignition coil. In addition, another kind of tachometer takes pulse signals from the generator and sends them to the tachometer circuit to explain and display the speed value. However, due to factors such as slipping of the generator belt, the value is not accurate.
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