Several different reasons will cause that your lights won't work properly.If the lights stop working completelyThere is a simple way to determine whether the light is faulty, that is to connect the light to a 12v DC power supply directly. Remove the light from the harness and connect it to the vehicle's battery or to a power source with a similar voltage. If the light is on, there should be a fault with the line. Go to the next step.Make sure the switch is still energizedCheck any loose connections through the wiring harness to make sure nothing is loose.Check that the ground/floor is still safe and properly installed.If the light is not lit from a direct power supply, the problem is with your light.Possible reasons for the partial working of the light barPoor grounding is usually the main cause of partial lighting. The best way to test whether there is defect in grounding is to change chassis grounding to battery negative terminal. It is wrong by checking the voltage of the light connector to determine whether it is improperly grounded. Maybe it is 14V + at the light connection, but the light still has bad grounding. That eventually leads to a difference in input power.Check the voltage of your vehicle's battery: Generally, this can be caused by low voltage. Lower than what the light bar required will reduce the brightness of the light bar, or you will see alternating patterns of LEDs. This can sometimes be solved by recharging or replacing the battery. Double check whether all wiring is properly connected in order to ensure there is no weak spot in the wiring.Why is my LED light bar flashing?Sampling current problem, due to the thermal effect of resistance, resistance value will change, if it becomes smaller, that will lead to an increase in output power, which will lead to chip overcurrent protection, the lightwill have a return power, then there is protection, so the light isflashing. If the sampling resistance increases, the light will darken or remain inactive, so the output voltage is very important. When current sampling, the resistor power must have a margin.There is something wrong with the light board. If theload oflight board does not match, the output voltage of chip will be overvoltage, resulting in chip overvoltage protection, then the light will also flash.Input voltageof LED light bar is not stable, that is to say, the supply voltage is not stable for chip, if the voltage is up and down, the current of output voltage is certainly not stable. So the led light bars will flash, too.Where to mount LED light bar?The light bar is mainly installed on the top of the car, the front and middle of the vehicle, or the position of the bumper. Using the existing hole, the front bumper is the easiest place to install the light bar. If you want to install smaller LED work lights, they usually come in pairs, either on the car's front safety bracket or in front of the rearview mirror. They are generally mounted on the roof of 3-4 rows, if there is a roof rack, they can also be mounted on the roof rack.Can LED light bars be mounted upside down?The light bars can be mounted upside down by mounting them on the top of the plastic bumper. The space there is completely open. When the bracket is flipped upside down, the light bar sits right between the top of the bumper and the license plate rack.How long do LED light bars last?According to the U.S. Department of Energy, quality LED lights should last 30,000 to 50,000 hours, some even longer. Some bulbs burn for 50,000 hours, while others don't, which depends on several factors, including the type of light fixture and operating temperature.When used outdoors, LED lights won’t be affected by low temperatures. However, they will be affected by heat. The radiator is placed at the bottom of the LED bulb to take the heat away, but when you have a closed housing, the heat has nowhere to go but back into the bulb. If you plan to use enclosed light fixtures, you’d better to look for LED bulbs designed for such housings.The first white LED lights hit the market in the mid-90s, and since then huge improvements have been made to improve the efficiency and service life of the original design. The average life span is 30,000 to 50,000 hours, but some can last up to 100,000 hours.How long will light bar last on battery?If your car has a built-in 2000mAh large capacity rechargeable lithium battery, charged via USB 5V plug charger, portable power pack or computer, when fully charged, it can be illuminated for about 50 hours in minimum mode, 12 hours in medium mode, and 4-5 hours in maximum mode.How to test LED light bar with battery?The first step is to make sure that the battery could provide enough power to the light bar, otherwise the light bar may not turn on. You can test your battery with a multimeter to make sure your battery has 12 volts when not working and 14 volts when working.Battery connection: Loose battery connections can limit the power of the vehicle and light bar. Any battery terminals that can be rotated by hand should be tightened in accordance with the vehicle manufacturer's specifications.The second step is to check the wire-harness of LED light barLight bar power and grounding: Find the power and grounding connections for the light bar and make sure they are securely connected and free of corrosion.Light bar fuse: If you have a LED bar, it will be equipped with a waterproof built-in fuse. Open the fuse holder cover and remove the fuse. Point the fuse of light bars at the light source and check the metal EMI gasket to make sure it is not blown. If you determine that the fuse is damaged, replace it with a fuse with the same rating for the light bar.Check relays: All light bars have 12 volt relays and some have 24 volt relays.The easiest way to test a relay is to replace it with another relay that works. If you have a backup light bar relay, then use it to see if the problem is solved, and if you are sure the light bar still doesn't work, proceed to the next step. Because the relay of light bars contains a mechanical switch that completes the circuit, you can place your finger on top of the relay and press the switch of light bars. If the relay is working, you could hear that the switch in the relay connect the circuit.When LED light bars make noiseAfter installing the light, the noise may be caused by the light, or it may be caused by driving too fast1. The radio is disturbed and produces noise, which is generally caused by wireless interference.Solution: Buy ferrite clips. Ferrite clips can repair radio interference.2.The sound of the light bar is very loud in the process of driving. This is because in the process of driving, the wind enters the bottom of the light bar and touches the radiator of the light bar, making it sound like a musical instrument.The solution: Buy a baseboard, cut it to the right length and size, and make a diffuser that changes the direction of the wind so it goes up and doesn't wind around the light bar and make noise.When LED lights were invented?As early as 1907, people found that some diodes made of semiconductor materials have the physical phenomenon of shining when positive conduction, but it has been 1969 for the production of red LED with a certain luminous efficiency.Blue LEDs were developed in 1994-1995 and commercialized in 1998. From 2000 to 2002, LED successfully entered the mobile phone backlight market under the continuous pursuit of cost effectiveness by the R&D personnel.Today, LED has been produced for more than 30 years, various types of LED, products secondary developped based on LED and products matched with LED (such as white LED driver) develops rapidly, new products come into the market continuously, and has developed into a new industry.Regarding LED technology research and development, the story most talked about is the contention between silicon carbide (SiC) and gallium nitride (GaN) when developing blue LED.Following the breakthrough of blue LED technology, white LED officially started a wide LED application range. From display, indicator and mobile phone light source to the brewing LC-TV backlight source, the door of various new opportunities have been constantly knocked open by creativity. LED is a semiconductor device developed from the three fifth group (III-V group) compound semiconductor after silicon (Si) semiconductor technology in the 1950s.The principle of lighting for LED is combining electrons and holes in semiconductors to give out photons, different from the light bulb which needs to operate at high temperature above 3000 degrees, also not like fluorescent lamp which uses high voltage to motivate electron beam, LED are the same as general electronic components, only require 2-4V voltage, can operate normally at room temperature, Therefore, its life span is longer than traditional light sources. The color of the LED is mainly determined by the amount of energy released by the combination of electrons and holes, that is determined by the energy gap of the semiconductor material used.The wavelength is very similar for te same kind of material , so the light color of each LED is very pure. Compared with the traditional light source, which is mixed with many colors, the LED can be said to be a digital light source. LED chip size can be cut randomly for the purpose, the commonly used size of 0.3-1.0mm or so, compared with the traditional bulb or fluorescent lamp, the volume is relatively small.When LED bulbs flicker1.Zero line chargedThis is a common situation. ① When the plumber wires, the alive circuit enters the LED bulb holder directly, and the zero line enters the control switch. Although the switch is off, there is still a current in a live wire. When the light reaches the switch, it still lights up slightly. Solution: In this case, adjust the wiring so that the switch controls the live wire.The switch controls the zero line to make the current flow through the lamp.② The plumber connected the wrong line when entering the main gate and the fire-fighting zero line was connected reversely, hence all the fire-fighting zero lines were reversed accidentally, resulting in all the switches controlling the zero line. The solution in this case is to adjust the incoming line only.③ If the switch controls the live line, use the traditional mechanical wall switch, or the switch shines, then the zero line is charged. Zero line charged is a very common phenomenon. If the grounding of zero line is not good, three-phase load of transformer is unbalanced, the line is too long, the line diameter is too fine, or the current of zero line is too large, it will charge the zero line.Solution:Re-ground the zero lineor perform low-voltage conversion. (This requires professionals for operation)2.The dual control switch is connectedincorrectly.Wrong connection, though can also be usedThere are several wiring modes for dual control switches. If the wrong connection is used, traditional incandescent bulbs will not light up, but LED lights will light up slightly when turned off due to direct current. The solution to this situation is to install the normal control live wiring method and rewire.Properly connected, any switch can cut off the powerThe wiring mode for double control switches: single link double control switches, three contacts on the back, namely L, L1, L2. Firstly, connect two L1 and L2, connect the live wire to the L contact of a double control switch, and connect the control loop wire to the L contact of another double control switch.3.Switches are equipped with indicator lights, using electronic and touch switchesThere is an indicator light inside the switch. When the lights are off, there will be a weak current.If the lamp uses electronic touch switch, such as infrared, voice control and remote switches. There is also a dim light when the lights are off. The solution to this situation is: ① Replace the switch. (2) the 500K resistor should be connected in parallel at the inlet of the lamp. However, professional and technical personnel should measure and install this method, while non-professional personnel should not operate at will. In addition, this method is not effective for low luminescence caused by the zero line charged or patch leakage.4.Leakage of unisolated drivers, light source patches and substratesTaking account of cost, many lamps adopt low quality resistance-capacitance to drive step-down, or the light source patch is of poor quality, and there is leakage between the patch and the substrate. The copper plating and capacitance effect for substrate can also lead to light leakage. Solution: Replace the lights.