Abstract: A lighting control system for a tractor is disclosed wherein the various lights on the tractor are controlled through a pair of switch devices. The first lighting control switch is a rotary switch controlling the macro positions of the lighting operation from an off position to selected combinations of groups of lights on the vehicle. The second lighting control switch is operable to select individual lights within respective groups. The electronic instrument cluster upon which the lighting control switches are mounted includes a memory to store the last selected combination of selected individual lights to permit the same combination of lights to illuminate automatically whenever the main control switch is moved from the off position to the appropriate on position.

Abstract: A universally applicable device for automatically turning on a vehicle's exterior lighting and related equipment upon activation of the vehicle's windshield wiper motor, and for keeping them turned on until the vehicle's ignition is turned off, or until the device is turned off by the vehicle's operator; also, for turning on all of a vehicle's exterior lighting and related equipment upon turning on the vehicle's ignition, and for keeping them turned on until the vehicle's ignition is turned off, or until the device is turned off by the vehicle's operator. A function switch is provided to allow the vehicle's operator to select lighting activation in response to the wiper motor, or to the ignition switch; or to turn the device off.

Abstract: Disclosure is a vehicle headlamp control system having a control circuit which can control the operation and the intensity of illumination of headlamps with ease. The vehicle headlamp control system has a control circuit for controlling the operations of headlamps on a vehicle at the start of the engine. The control circuit operates to adjust the duty ratios of driving pulse currents applied to the headlamps through transistors, thereby to adjust the intensities of illumination of the headlamps. The control circuit has elements for adjusting the duty ratios. With the system, the intensities of illumination of the headlamps can be adjusted with ease.

Abstract: A pulse width dimming system responsive to low frequency pulse width modulated signals of various duty cycles employs a single charging capacitor in a charge pump circuit to develop voltage signals for controlling current through a field effect transistor used to control dimming of the intensity of lamps in a vehicle instrument panel.

Abstract: A device for automatically correcting the elevation angle of at least one vehicle headlight during changes in the attitude of said vehicle, the device being of the type comprising at least two lighting sensors integrated in the headlight and constrained to move therewith, the two sensors being disposed to detect the brightness of the road in the field of illumination of the headlight in two different directions at two predetermined angles relative to a reference direction of said headlight, an actuator suitable for varying the angle of inclination of the headlight relative to the vehicle, and processor means suitable for generating an actuator control signal as a function of the signals delivered by the sensors which are essentially proportional to the quantity of light that each of them receives.

Abstract: Disclosed is a lighting apparatus for a vehicular discharge lamp which prevents the occurrence of an electric shock when the status of a vehicle is changed while the discharge lamp is on, such as when the hood of the vehicle is opened for inspection or repair. A hood open/close detector detects that the hood is opened while the discharge lamp is lit, and upon reception of a detection signal from the detector, the power supply/cutoff circuit opens a cutoff switch means to stop power supply from a battery to a lighting circuit, turning off the discharge lamp. In this manner, a person who opens a hood for work can be kept out of danger of a high voltage that is supplied to the discharge lamp.

Abstract: A convienience feature is added to a DRL circuit to enable the driver to temporarily override the DRL system in situations where it is appropriate, such as when the vehicle is approaching weigh scales or entering a tunnel. The convenience feature is embodied in a convenience circuit that is interposed in the current feed path to the DRL circuit. The convenience circuit comprises a momentary switch that is actuated by the driver and a timing relay module that is responsive to the actuation of the momentary switch.

Abstract: A towed vehicle conversion and isolation circuit is disclosed for coupling dual stop and turn indicator lamps on a towed vehicle to towing vehicles having either dual stop and turn lamps or separate stop and turn lamps. Additionally, the circuit provides a small load to the towing vehicle signaling circuit and isolates the towed vehicle indicator lamps from the towing vehicle signal circuits. Furthermore, the circuit may be coupled to the towed vehicle brake coils to illuminate the towed vehicle lamps responsive to manual actuation of the towed vehicle brake for providing energizing current to the indicator lamps.

Abstract: Improved windshield wiper light circuitry for a device that automatically turns on vehicle head lights and other lights whenever the wipers are on is provided. A double-pole, single-throw relay switch (1) is positioned in vehicle circuitry between the ignition switch (13) and the light switch (14). One of the two poles has as electrical lead (3) to the low-beam head lights and the other (4) to the rear lights, park lights and side lights together. A diode rectifier (12) is provided in circuitry between a line (9) for continuous operation and a line (7) for intermittent operation of a wiper motor (11). A light shut-off delay provided by use of a timer (17) acts as a safety sentry light for a period after the ignition switch (13) is deactivated. A single pole relay switch (19) enables this circuitry to operation any 12-volt windshield wiper system.

Abstract: A lighting system for a motor driven vehicle having a headlight for connection to a power source and a lighting switch operatively connected to the headlight for selectively supplying power thereto. A first detector member for detecting the on and off positions of the lighting switch and for generating a signal responsive thereto. A second detector member for detecting a stopped state and movement of the vehicle and for generating a signal responsive thereto. A converter operatively connected to the headlight and for connection to a power source for selectively adjusting the voltage supplied to the headlight in accordance with signals generated by the first and second detector members for dimming the headlight when the lighting switch is in an off position and during a stopped state of the vehicle.

Abstract: A headlight assembly including a pair of headlight units each having first and second headlights. The first headlight has a halogen bulb having a high-beam filament for illuminating a range faraway from the vehicle and an auxiliary low-beam filament for illuminating a range in the vicinity of the vehicle. The second headlight has a discharge bulb for a low-beam for illuminating a range in the vicinity of the vehicle. The headlight assembly further includes a lighting control circuit for controlling lighting and turning-off of these headlights in such ways that both the bulbs of the first and second lamps are lighted during main lighting which illuminates the range faraway from the vehicle with a high-beam and the range close to the vehicle with a low-beam, that the bulbs of the second headlights are lighted during dimmer lighting which illuminates the range in the vicinity of the vehicle with a low-beam, and that only the bulbs of the first headlights are lighted during passing.

Abstract: The disclosed circuit for actuating headlights has two time delay circuits, an AND gate, a power relay, and connections for appropriate installation to the circuitry of the automobile. When windshield wipers are operated, a pulse of the windshield wiper motor causes the first time delay circuit and the second time delay circuit to run timing cycles. The timing cycle of the first circuit is shorter than the timing cycle of the second circuit, and the first circuit is restarted with each pulse of the windshield wiper motor. Each timing delay unit has an output signal which is a logical "one" when a cycle is being run and a logical "zero" when a cycle is not being run. When the AND gate receives logical zeros from the second time delay circuit, and logical ones from the first time delay circuit, windshield wipers are in use and the headlights and parking lights are switched on. A daylight detection circuit may be incorporated to provide safe use of the unit in dusk hours.

Abstract: A vehicle's input switches relating to ignition, lights and moisture or rain provide responsive inputs that feed through a digital logic circuit to outputs of an electronic switching device for automatically activating the vehicle's lights and wipers.An alarm may be activated if certain input switches are turned on when the ignition is off.The digital logic circuit may be discrete, a programmable read only memory (PROM) or a programmable logic array (PLA).The electronic switching device may constitute a driver circuit and an integrated circuit which includes both a relay switching circuit and a switched circuit, for example a metal-oxide-semiconductor (MOS) driver and a power metal-oxide-semiconductor field-effect-transistor (MOSFET) integrated circuit.

Abstract: An automatic headlamp dimmer system for switching a vehicle's headlamps from high beam to low beam when lights from another vehicle are detected in front of the vehicle. To prevent spurious responses to reflected light from signs and other sources, the dimmer system includes a light detector which is responsive only to infrared light. Also, unwanted responses to flashing lights are avoided by detecting the presence of a periodically varying light signal, and inhibiting switching between high and low beams in response thereto. The system is also capable of sensing the activation of windshield wipers and preventing headlamp switching caused by interruption of light to the system's light sensor by action of the wiper blades.

Abstract: An automatic driving lights circuit for a vehicle electrical system in response to the operation of a windshield wiper motor. The driving lights circuit operates independently of the headlights switch to turn on and off the driving lights each time the wiper motor is turned on and off. Additionally, the circuir continually operates the driving lights when the wiper is operating intermittently.

Abstract: A lighting circuit for a vehicular discharge lamp has a DC voltage booster circuit, a control circuit, and a voltage drop detector. The booster circuit boosts an input voltage from a DC voltage input terminal to provide an output voltage to be applied to the discharge lamp. The control circuit functions for varying the output voltage of the DC booster circuit to effect lighting control including constant power control of the discharge lamp. The voltage drop detector detects a DC input voltage applied to the booster circuit. In response to a signal received from the voltage drop detector in accordance with a drop of the DC input voltage, the control circuit performs voltage boosting control to set power supplied to the dicharge lamp lower than the rated power. It is therefore possible to suppress an increase in current consumption and a consequent increase in generated heat when the DC input voltage drops.

Abstract: An apparatus within a vehicle including a plurality of high beams in electrical communication with an automatic circuit to direct voltage to each associated high beam, wherein a photo-transistor is arranged in parallel circuitry to a relay coil and resistor, with the junction transistor arranged to interface between the first and the second parallel circuit, including the photo-transistor and adjustable resistor respectively. A modified detector circuit includes a second resistor in series with the resistor, and a third resistor in parallel relationship to the relay coil to effect a time delay in actuation of the high beam members of the vehicle. A third junction transistor is arranged in a third circuit parallel to the first and second circuit to direct current to the respective high beam for increased sensitivity relative to the incoming light source from a remote vehicle.

Abstract: A lighting control circuit for head lamp has three relays with coils. When a lighting switch is turned on, high beams of right and left head lamps are lit. When the dimmer switch is turned on, low beams of right and left head lamps are lit. When the lighting switch is turned off, right and left head lamps are lit by low voltage which is equal to 50% of a rated voltage so as to improve the durability of the head lamps.

Abstract: A power supply circuit for an arc lamp, in particular for a motor vehicle headlight, the power supply circuit being wherein it comprises: means for converting electricity from a low voltage DC supply such as a vehicle battery into an alternating voltage of amplitude which is variable as a function of the state of the lamp; and a voltage-raising transformer, the variable alternating voltage being applied to the primary winding of the transformer and the lamp being connected to the terminals of the secondary winding of the transformer, either directly or else by means of non-inductive components.

Abstract: A lamp containing a fill of xenon, mercury and metal halide is disclosed which serves as a light source for lighting applications and is particularly suitable for automotive forward lighting applications. The xenon ingredient operates to provide for instant light necessary for automotive applications, whereas, the mercury and metal halide ingredients operate to provide for a long life, high efficiency lamp relative to either a xenon or tungsten lamp. The dimensions of the xenon-metal halide lamp of the present invention are approximately three-fifths (3/5) of those of a typical tungsten lamp utilized for automotive forward lighting applications. The reduced dimensions of the xenon-metal halide lamp allows for correspondingly reduced dimensions of a related reflector for such a xenon-metal halide lamp which accommodates the needs of aerodynamically styled automobiles.

Abstract: A parking lamp operating system reduces the electrical load on the battery of a vehicle, such as a truck, during periods when the vehicle engine is off but the parking lamps of the vehicle remain on wherein a switched signal input from the battery is modulated to provide a pulse-width-modulated output to the gate of a power transistor having a power input from the battery and an output to the parking lamps. The pulsed signal causes the transistor to intermittently switch the power to the lamps thereby reducing the effective voltage thereto while providing sufficient light output to be observed. The modulator may be bypassed by a second signal line connected to the vehicle alternator to provide a continuous signal to the transistor gate, thereby providing full power to the lamps when the engine is running.

Abstract: A daytime running light circuit is integrated with the existing headlight circuit of an automotive vehicle. The daytime running light circuit functions to automatically illuminate the headlights at reduced intensity when the vehicle is running and the headlight switch is turned off. Any time, however, that the headlight switch is turned on, the headlights are illuminated at full intensity. The daytime running light circuit includes a day relay and a night relay. The night relay is responsive to the headlight switch being turned on for preventing operation of the daytime relay which would otherwise illuminate the headlamps at reduced intensity if the vehicle were running and the headlight switch off. When the headlight switch is off, the night relay enables the day relay to be operated whenever the vehicle is running. Indication that the vehicle is running is obtained from the alternator "R" terminal.

Abstract: A photoelectrically controlled corner light system for a vehicle includes corner lights adjacent to headlights which are disposed in the right and left corners of the vehicle. The corner lights switched by operating a headlight turn lever are connected to a light detecting sensor for operatively controlling the brightness of its illumination. The light detecting sensors detects the light of headlights from opposing vehicles and controls the brightness of the illumination in the light system to prevent the view of a driver of the opposing vehicle from being disturbed.

Abstract: An automatic light-extinguishing circuit (60) is disclosed for extinguishing, for example, the headlights (30) of an automobile some interval of time after the ignition switch (54) is opened. The circuit includes a temperature-actuated switch (72), switching relay (78), and diode (86). The heating element (74) of the temperature-actuated switch and a solenoid (80) of the switching relay are energized upon closure of the ignition switch, closing two normally open switch element (82 and 84). In this condition, current passes through the switch elements of the switching relay to the headlights and taillights. When the heating element causes the temperature of a switch element (76) to rise sufficiently, the switch element closes, forming an alternative path of current to the solenoid. When the ignition switch is opened, this path is maintained, ensuring continued flow of current to the headlights and taillights until the switch element cools sufficiently to open.

Abstract: A control system for turning on the headlights (and parking lights) of an automobile when the windshield wipers are turned on, has a gating circuit that operates relay circuits to the headlights, the gating circuit electronically latching "in" the headlight relay circuit so that the headlights remain on when the windshield wiper is turned off in order to avoid inadvertent turning off of the hedlights at night time and the gate circuit electronically turning off the headlight (and parking light) relay circuits whenever the headlight switch is turned on or whenever the ignition is turned off, thus assuring that the headlights will remain on until the headlights and ignition switches are turned off. The relay circuits controlled by the gating circuit may operate a mechanically or electrically latched relay device to hold the headlights (and parking lights) on until the relay circuit controlled by the gating circuit operates the mechanically or electrically latched relay device to turn the headlights off.

Abstract: An automatic car lamps lighting controller to provide warning light in the daytime as well as in the night. The system includes an induction coil for detecting the start up of the car engine, an amplifier circuit, a comparator, control relays, and a night control circuit. As soon as the car is started, the front and the rear location lamp of the car being automatically turned on; the car front lamps and dash lamps automatically turned on in the night. The system enables the instant vehicle (car) to be readily seen by the drivers of other vehicles even though the driver of the instant vehicle neglects or refuses to manually turn on the road illumination lamps or vehicle location (parking) lamps.

Abstract: A daytime running light circuit is integrated with the existing headlight circuit of an automotive vehicle. The daytime running light circuit functions to automatically illuminate the headlights at reduced intensity when the vehicle is running and the headlight switch is turned off. Any time, however, that the headlight switch is turned on, the headlights are illuminated at full intensity. The daytime running light circuit comprises a day relay and a night relay. The night relay is responsive to the headlight switch being turned on for preventing operation of the daytime relay which would otherwise illuminate the headlamps at reduced intensity if the vehicle were running and the headlight switch off. When the headlight switch is off, the night relay enables the day relay to be operated whenever the vehicle is running. Indication that the vehicle is running is obtained from the alternator "R" terminal.

Abstract: A power supply circuit for automotive headlamps includes an electrical wire establishing communication between one of the headlamps and a power source at a first position of a combination switch, and a control unit selectively establishing communication between the other headlamp and the power source at the first position and between both of the headlamps and the power source in series at a second position of the combination switch.

Abstract: Turning on either headlights or parking lights pulses a first control circuit and energizes a relay, closing normally open contacts in the light circuits. The closing of the contacts energizes a second control circuit which holds the relay on and supplies power to timers. Turning off an ignition switch starts a short headlight timer and a long parking light timer. The timers have outputs connected to disable the second control circuit and to thereby de-energize the relay. The output of the short timer is grounded through the headlights when the headlights are in a low resistance off condition.

Abstract: A combination lamp includes a first light and a second light. The first light includes a discharge lamp and serves to generate light. The second light serves to generate light and also heat, and thereby serves to heat the discharge lamp. Accordingly, the second light can preheat the discharge lamp. This preheating allows the discharge lamp to produce adequate luminous energy immediately when the discharge lamp is turned on.

Abstract: In an apparatus for controlling a headlight of a vehicle, a light from a preceding or oncoming vehicle can be detected without being disturbed by a light reflected on guardrails and the like, or light from a traffic signal, street lights and the like, and the illumination area of the headlight can be suitably adjusted without unnecessary switching of an illumination mode of the headlight. This control is carried out by receiving a light impinging on the front end of the vehicle by a light receiving member divided into a plurality of regions, by carrying out a comparison and discrimination between the light detection signals from the plurality of regions, and based on a result thereof, by selecting an appropriate illumination mode of the headlight.

Abstract: The present invention utilizes a dimmer switch for alternating the lighting direction of a vehicle headlamp, but does so utilizing control apparatus that ensures that only low beam-directed light is emitted by the headlamp when the headlamp is turned ON. The possiblity which might be presented if oncoming traffic is suddenly met with high beam-directed light when an automobile driver turns his headlamps ON is thereby averted.

Abstract: Disclosed is a xenon lamp used for lighting applications and which is particularly suitable for automobile applications such as headlamps. The benefits of such usage, relative to incandescent lamps commonly employed for automotive forward lighting applications along with discharge lamps for lighting application, are primarily related to the size, shape, quality and concentration of the light generated by the xenon lamp and the ability to selectively move the position of the generated light relative to the reflector in which the xenon lamp is housed. The xenon lamp also provides the ability for the light to be generated by excitation of a D.C. source so as to be first positioned relative to the reflector to serve as the light source for low beam applications and then moved to a second position relative to the reflector to serve as the light source for high beam applications.

Abstract: A method and apparatus for automatically responding to headlamp radiation from oncoming vehicles to down-switch beam patterns in a tri-beam headlamp system in an automotive vehicle. A mid-beam sensor is provided to detect only that headlamp radiation from oncoming vehicles present within the defined high intensity projection areas of the mid-beam pattern and functions in conjunction with a conventional automatic dimmer sensor and a unique control circuit to achieve appropriate and automatic down-switching.

Abstract: A power supply circuit for automotive headlamp assemblies includes a switch assembly selectively operable between a first position at which the electrical power is supplied to high-beam valves of the headlamp assemblies, and a second position at which the electrical power is supplied to low-beam valves of the headlamp assemblies. The power supply circuit also includes means for establishing communication between a power source and the low-beam valves at the first position, so as to turn the low-beam valves on whenever the high-beam valves are turned on.

Abstract: The invention consists of an electrical circuit for a vehicle headlight system whereby the conventional parallel circuit connection of headlights is automatically converted into a series circuit connection under conditions appropriate for daytime running lights, whereby the light output of the headlights is reduced as compared to that in conventional headlight circuit mode, and a method for interconnecting such circuit with conventional headlight systems.

Abstract: A plug in circuit component is provided for switching headlights of vehicles such as automobiles between two positions; full beam and half beam. When the headlight is switched from low to high beam, the low beam disappears in conventional systems, however with the present invention the low beam remains illuminated even when the high beam setting is on and this is accomplished preferably by the use of a diode in the device.

Abstract: Apparatus for causing an external light system of a motor vehicle to be actuated when the vehicle engine is running, the vehicle having an electrical battery associated with the engine, and the running of the engine causing an AC signal to appear with a DC component at a terminal of the battery. The apparatus has an electrical circuit with a filter for filtering the DC component from the AC signal to provide a filtered AC signal indicating an engine running condition. The filtered AC signal or other engine running signal obtained from the filtered AC signal is compared with a predetermined value and an actuating signal is provided when the engine running signal is above the predetermined value. An actuator responsive to receipt of the actuating signal causes the external light system of the vehicle to be turned on.

Abstract: Protection for D.C. electrical circuit branches against incipient overloads comprises the use of semiconductor devices known as intelligent switches. An intelligent switch comprises a main controlled conduction path whose conductivity is controlled by an external control input. The semiconductor architecture is configured to possess internal self-protection for the main controlled conduction path against incipient current and/or temperature rises exceeding the device's rating by rendering the main controlled conduction path non-conductive when such incipient conditions are sensed. The invention, recognizing that this internal self-protection attribute can be used also to provide protection for external circuit components connected to the switch in the branch, further comprises the elimination of external protective devices from the branch such that the intelligent switch itself provides the entire overload protection within the branch.

Abstract: In order to permit the simultaneous variation of the illumination of a clock and the illumination of instruments included in an instrument panel of an automotive vehicle or the like, a single illumination control device is connected with the ignition switch and a lighting control switch in a manner that when the lighting switch is on, the voltage applied to the bulbs which illuminate the clock and the instrument panel are simultaneously controlled while the tail lamp bulbs are constantly energized to their normal level when only the ignition switch is on, current is fed to the clock illumination bulb. The resistance inherently provided by the plurality of bulbs used in the instrument panel and tail lamp assemblies prevents illumination of the same under such circumstances.

Abstract: The process and the device enable the electrical powering of a circuit having a conductor (1) with high thermal inertia by means of a transistor (3) with low thermal inertia. According to the invention, the device comprises a current limiter circuit (4,5,7,11), a voltage detector circuit (8) and a control microprocessor (6) which, according to a pre-established program, controls the flowing and stoppage of current in the power transistor (3) controlling the powering of the conductor (1) with high thermal inertia.Application to the control of lights in automobile vehicles.

Abstract: A main battery disconnection alarm and headlight warning circuit in which the main battery charges and maintains a backup battery in full charge, and when the main battery is disconnected or damaged, the backup battery provides power to an alarm and a control circuit triggers a siren to give warning, and a headlight warning circuit which triggers a siren to give a different warning sound from the main battery disconnection alarm.

Abstract: An adapter unit for interfacing the existing brake and turn signal light system of a vehicle with the light system of a trailer. The adapter unit includes a first relay having a single coil and a pair of contacts relatively movable to a closed circuit condition in response to energization of the coil and biased to an open circuit condition. A second relay has a single coil and a pair of contacts also relatively movable to a closed circuit condition in response to energization of its coil and biased to an open circuit condition. The coils are interconnected with the vehicle light system. The contacts are interconnected with the trailer light system and are also connected to the vehicle battery through a different circuit than the one including the turn signal flasher of the vehicle.

Abstract: A light control circuit includes a latching circuit actuated by a manually actuated switch to, in turn, activate a solid-state switch coupled to supply power to one or more lamps. The latching circuit is reset by a diode coupled to the door actuated switches such that in the event the interior lamp or lamps are manually operated and a door subsequently opened, the lamps will be extinguished upon the closing of the door regardless of the prior manual activation of the lamps.

Abstract: A light control apparatus for a vehicle is integrated with headlamp driving relays, a light sensor, a lighting switch which selects a manual mode or an automatic mode, and a control unit which controls the relays in accordance with the light sensor output when the lighting switch selects the automatic mode and turns on or off the headlamps. Two power source systems and two headlamp driving systems are provided. The signal level of a given terminal of the control unit is detected and is input to the microcomputer of the control unit. The microcomputer judges whether or not trouble has occurred by detecting a level difference. An alarm indication is given by a lamp or a buzzer if trouble is detected.

Abstract: An automatic vehicle headlamp dimming control is the type having an operator controlled first voltage divider across a power supply, a light sensitive resistance connected in electrical series with an electrically controlled variable resistance in a second voltage divider across the output of the first voltage divider, an energizing circuit adapted to energize the headlamp system from the power supply at high or low intensity in response to the output of the second voltage divider compared to a fixed reference voltage and first electric feedback means from the energizing circuit to the electrically controlled variable resistance for producing hysteresis feedback.

Abstract: A system of daylight running lights utilizing the front turn signal lights of a vehicle incorporates a solenoid coil and a double pole single throw switch, such that when the coil is activated, both poles are closed. A connection from the ignition circuit to the coil is such that when the ignition circuit is at "run", power is available to said coil. The circuit is such as to prevent the coil from being grounded, thus de-activating the coil, whenever the turn signal switch is on, or whenever the headlight switch is on. When either of these conditions applies, the DPST switch is open. The coil is grounded and thus activated whenever the turn signal switch and the headlight switch are both off. The circuit is such that power can be fed through the DPST switch, when closed, to energize both signal lights simultaneously, thus providing daytime running lights.

Abstract: A vehicle light control system for controlling the low beam of headlights of a vehicle. The system comprises a first and a second switching device with the first switching device being in a normally conductive state and the second device being in a normally non-conductive state. The first switching device is connected to the alternator of a vehicle to tap a supply voltage therefrom. The second conductive device is condition by the first conductive device and is also connected to a supply voltage to feed the low beams of the headlights when conditioned to do so by the first switching device. The headlight switch of the vehicle when switched on the high beams cuts off the first switching device and the supply voltage to the low beams. The supply voltage fed to the low beams is further reduced whereby not to subject the low beams to full intensity whereby to prolong their life span.

Abstract: A motor vehicle daytime running light circuit is disclosed in which the high beam headlights are energized at a reduced intensity in response to a predetermined vehicle operating condition including, for example, the headlight switch being in the off position. Power to the high beam headlights is supplied through a field-effect transistor that is modulated by an oscillator operating at a frequency sufficient to maintain the headlights at a constant intensity. Circuitry that senses the predetermined vehicle operating condition enables the oscillator and disables a high beam indicator.

Abstract: The invention consists of an electrical circuit for a vehicle headlight system whereby the conventional parallel circuit connection of headlights is automatically converted into a series circuit connection under conditions appropriate for daytime running lights, whereby the light output of the headlights is reduced as compared to that in conventional headlight circuit mode, and a method for interconnecting such circuit with conventional headlight systems.