A flasher circuit included in a vehicular turn signal indicator system has a
flashing
control circuit, a flashing relay, a current detecting resistor, and a switching
circuit. The control circuit detects a voltage drop across the resistor during
driving of light bulb indicator lamps and light emitting diode (LED) indicator
lamps of the system. Each LED lamp is configured to output a disconnection signal
if at least one of their LEDs is disconnected during the driving. The signal turns
on a transistor of a switching circuit, resulting in short across the resistor.
As a result, the voltage drop is lowered equal to or under the threshold value,
and the control circuit starts the disconnection detection.
