Automotive headlight control firewire type circuit diagram current flow

The headlight circuit is generally divided into two forms of control, direct control and indirect control, and indirect control is divided into relay control and electronic control of two kinds.

If it is directly controlled by the headlight switch, the current flow is: battery positive - fuse - headlight switch - light switch - bulb - hitch (battery negative).

If it's indirectly controlled (relay, etc.) then there are two circuits, the control circuit and the actuation circuit.

Direction of current in the control circuit: positive battery terminal - electric door lock - switch (control device) - relay coil - hitch.

The direction of current in the execution circuit: battery positive terminal - fuse - relay contacts (actuator) - light bulb - iron.