The pump truck instrument power indicator light is a hard-wired feedback structure and is directly connected to ground.
For hardwired lines, there are two plugs on the generator, one is commonly called the regulator plug and the other is called B+. If the regulator plug is disconnected, the battery indicator light will not come on.
As for the light not illuminating the car as you mentioned, this is normal. If it won't turn the car on and turn on, there is a problem. You can connect the power regulator plug to the negative pole.
1. The connection wire between the battery and the generator is broken or fallen.
2. The generator does not generate electricity. This may be caused by a short circuit in the silicon diode, a short circuit in the stator winding or magnetic field or a ground fault, the brush is stuck in the brush holder or in the insulation of the magnetic field Borne F Damage to the earth.
3. The regulator is defective. For example, incorrect adjustment causes the voltage to be too low, low speed contacts are oxidized, ablated, dirty, or they touch high speed contacts without excitation current. .