Abstract: A control system for automatically turning on and off at least some of the lights of a vehicle, such as an automobile. The control system includes a vacuum switch connected to a vacuum source on the engine. A vacuum delay valve is interposed between the vacuum source and the vacuum switch. When the engine is running, a vacuum produced at the vacuum source will actuate the vacuum switch to close a set of normally open contacts. When the contacts close, a source of electrical power is connected to at least the low beams of the headlights to illuminate the low beams during the operation of the engine without intervention by the driver. The vacuum delay valve ensures that intermittent interruptions of the vacuum at the source, e.g. as might be caused by vehicle acceleration, will not open the vacuum switch when the engine is still running.