what causes a tachometer to stop working

• 2021-12-30

The tachometer maybe not work. The tachometer is generally set in the instrument panel and placed symmetrically with the speedometer. The tachometer works according to the magnetic principle. It receives the pulse signal generated when the primary current in the ignition coil is interrupted and converts this signal into a displayed speed value. The faster the engine speed, the more pulses generated by the ignition coil, and the greater the speed value displayed on the table.

And it may be that the engine idle speed is very high. Check whether the basic water and oil levels are normal.

First, check whether the black 3-hole plug on the back of the tachometer is in good contact with the socket and whether the voltage is normal.

Connection of 3 terminals:

Terminal A is the negative pole of the power supply, which is grounded after being connected with the brown wire on the 14 hole white socket of the instrument panel (all grounding points on the instrument panel are gathered together by the brown wire, wrapped with adhesive tape and connected to a terminal of the 14 hole white socket of the instrument panel, and then led to the grounding terminal of the instrument line by the brown wire);

Terminal B is the positive pole of the power supply and is connected to the ignition switch "15" through the 14 hole black socket. When the ignition switch is turned on, the voltage on terminal B shall be equal to the power supply voltage. If the voltage is zero, check whether there is voltage on the wire on the black socket of terminal 14 of the instrument panel (all power supplies on the instrument panel are introduced from the ignition switch terminal 15 through the black wire);

Terminal C is a signal input terminal, which is connected with the red / black wire on the 14 hole white socket of the instrument panel. A multimeter can be used to detect whether there is signal voltage on terminal C.

If the voltage on each terminal of the 3-hole socket is normal, it indicates that the line is good. The fault occurs in the tachometer and should be repaired or replaced. If the connecting wire is loose, it shall be tightened again. If the connection is in poor contact, the dirt and rust shall be removed; If the connector is found damaged, repair or replace it.