When the ignition switch is turned on to the start position, the electromagnetic switch does not respond. Under normal circumstances, when the ignition switch is placed in the start position, a "click" sound should be heard from the electromagnetic switch. Common faults of the starter electromagnetic switch during use include:

 ① Sometimes it attracts and sometimes it does not attract, or it attracts when the car is cold but not when it is hot. Sometimes it can attract when the power supply is directly connected to the switch terminal with a screwdriver, but the electromagnetic switch does not attract when the start button or relay is working. As the temperature of the hot car increases, the electromagnetic attraction becomes worse. This fault is mostly caused by insufficient attraction of the electromagnetic switch.

 ② When starting, the electromagnetic switch cannot be reset after the card is issued. When the start button is released, the starter continues to run and stops working only when the power is cut off.

 ③ When the starter starts, periodic noise is emitted from the electromagnetic switch, but the starter does not turn. The electromagnetic starter switch is a motor circuit control device composed of a fixed iron core, a movable iron core and a magnetic coil. When the power is turned on, the magnetic field generated by the magnetic coil causes the movable iron core to move, and the one-way meshing gear is pushed out through the starter moving fork to mesh with the flywheel gear ring and drive it to rotate. Causes of the failure: 

① The movable iron core is too tight with the switch shaft and the coil housing and moves inflexibly; 

② The surface of the switch contact and the contact plate are not smooth, burned and dry; 

③ The contact plate is uneven and the fixing nut of the power terminal is loose; 

④ The coil is short-circuited, open-circuited or has poor contact, etc.