Warning lamp, charging: Notes
The charging warning lamp is located in the top right-hand corner and informs the driver whether the generator is charging or not.
The lamp is supplied with current in the main instrument unit and grounded by the generator via terminal 3 (K20).
If the generator does not rotate or charge for any reason, the indicator lamp circuit is grounded via the regulator through the generator's field winding, causing the lamp to light up. At the same time the central warning lamp lights up and, at engine speeds above 310 rpm, the MIU sends a request to the SID unit for activation of an acoustic signal.
When the generator is charging, its D+ and B+ terminals will have the same voltage. Both terminals of the warning lamp will then be supplied with this same voltage and the lamp goes out.
A resistor is connected in parallel with the lamp. This resistor ensures that magnetizing current is supplied to the generator on starting even if the lamp is faulty.
A diode is connected in series with the resistor/lamp. This diode prevents the lamp from glowing at high charging voltages.