① The horn sounds and the headlights turn on. Use a screwdriver or a wire to test the fire on the ignition coil "-" terminal. If there is no fire, open the circuit between the ignition coil low-voltage terminal and the ammeter.

Press the ignition coil "switch" → ignition coil "switch-power" terminal → ignition switch → ammeter in order to test the fire, and diagnose the location of the open circuit fault according to the fire and no fire. If the terminal is not firmly connected to the wire or the connection is poor, the terminal should be cleaned and the fixing nut tightened; if a certain section of the wire is broken, replace the section of wire, and the replaced wire should be the same as the original wire.

② The horn does not sound and the headlights do not turn on. Test the fire on the starter terminal with a wire. If there is a fire, the fault is a circuit break between the starter terminal and the ammeter; if there is no fire, the fault is a lack of battery power or a line failure. The battery is low and should be recharged; the line is disconnected and should be reconnected.

③ Use a screwdriver to test the fire on the “-” terminal of the ignition coil. If there is fire, test the fire between the movable contact arm of the distributor and the base plate. If there is a fire, it is a contact failure (such as contact ablation, too dirty, can not be closed, etc.), you can use "platinum sand bar" to grind the contact and adjust the contact gap to remove the fault; if there is no fire, turn Go to the next step.

④ Test the fire at the distributor's insulation post and the distributor housing. If there is no fire, the wire between the distributor's insulation post and the ignition coil “-” connection post is broken; Open wire failure between the posts.

If the terminal is in bad contact with the wire and the power is cut off, the terminal and the wire head should be cleaned and fastened; if a certain section of the wire is broken, replace it with the same specification wire.