Light Relays, Sensors, Control Modules

Automotive lighting is what helps car aficionados stay safe and sound behind the wheel during poor visibility conditions and at night. The simplest light circuit consists of a switch, a bulb, and a power source. The lighting circuits in modern vehicles are far more complex, however, and usually include relays, sensors, and control modules. Control modules govern circuits where more than simple on/off is required; relays allow a low-current circuit to control a high-current circuit; and sensors affect function, enabling automatic operation or adjustment.

Relays are the most common additional component found in light circuits and controlled by the low power signal, sending a signal to the circuit breaker as soon as the fault in the lighting system occurs. They are used for protection against any voltage surges and to simplify component design and installation. Many lighting circuits draw high current and heavier gauge wire must be used. By controlling the load with a relay, much lighter gauge wire and a smaller, lighter-duty switch can be used in the circuit between the switch and the relay, making switch construction and mounting location in the vehicle easier. Many lighting circuits are controlled through a body control computer. Using a relay in the circuit protects the computer from expensive damage that could be caused by high current.

One of the most common lighting control module is found in the Daytime Running Lights (DRL) system. DRLs automatically activate the headlights, usually at reduced intensity, when the engine is running. The increased vehicle visibility makes driving safer during daylight hours, and the driver can override the system at any time by turning on the headlights. Some systems use a resistor to reduce voltage to the headlights for reduced light intensity, but many systems use pulse width modulation and a control module that has a duty-cycle to reduce output. In a duty cycle output, power is rapidly switched on and off as it is supplied to the lights. The “off” time reduces power supplied by a desired percentage and so reduces the headlight intensity.

Sensors are used in some lighting system to affect their operation. Photocell sensors detect ambient lighting and are used in automatic on/off headlight systems and with automatic headlight dimming. In the former system the photocell sensor signals a control module when the level of ambient lighting decreases to a certain level, and the module energizes a relay that in turn sends power to the headlights. In the latter system the headlights are switched from high to low beam when the photocell sensor detects light from oncoming vehicles. Vehicles with self-leveling headlights have a level sensor that detects changes in vehicle tilt caused by additional passengers or cargo, signaling a leveling motor that adjusts the angle of the headlights accordingly.

Whether you’re looking for a premium-grade light relay to ensure effective protection for the circuit from overcurrents, control module to safeguard the system from over/under charging and allow you to turned on/off the lights automatically at programmable time intervals, or sensors to detect how bright/dark the light is, we’ve got you covered. Our virtual shelves are stacked to the ceiling with a diverse variety of top-notch light relays, sensors, and control modules from leading manufacturers in premier restoration part industry. Designed with high precision using the finest materials, these components look, fit, and perform as perfectly as your original parts. They’re bound to help restore your lighting system’s protection and efficiency so you can enjoy superior level of illumination needed to safely operate your vehicle, while having confidence that it stays safe from heavy currents.