Failure indicator for vehicle lights - with delay circuit for testing indicator lamp when switched on

摘要

The vehicle lights are grouped in pairs (1, 2) with each pair linked to a failure indicator circuit which illuminates a warning lamp (8) on the dashboard when one of the pair fails. The warning is activated by the current imbalance between the two lamps when one fails. A secondary monitor circuit (10) is fitted to operate the warning indicator every time the ignition is switched on. The driver has a clear indication that the warning indicator bulb is operating every time the ignition is switched on. A simple time delay circuit cancels the warning light after a set time interval.