Low Beam Headlight Issues in Car and How to fix it?

Imagine you have an urgent work at night and you have to drive your car but you couldn’t make your car headlights turn on. You have to drive so to focus on road in traffic. You turned the low beam switch on but still the headlight is not glowing properly. What would you do? What would be the reason? Read the article to find out how to fix car headlight issues

Low beam headlights

Low beam headlights is the headlight set in such a way that it focuses on lower side and a limited area infront of your car. This setting is available almost in every vehicle having headlights. Low beam is used at night, in heavy traffic and in rains. The headlights get power supply from battery and alternator. The relay connects the headlight to the battery. Basically the relay makes the headlight glow. Relay is controlled by switches; switches can activate as well as deactivate the relay. Fuses are the sacrificial arrangements that protect the bulbs, the wiring and other component from high voltage. Relays also make the low beam lights to turn on from high beam. Failure of electrical system, wiring, bulbs, relays, fuse and switches will surely lead the headlights to stop glowing.

Reasons for not working of low beam headlights

Damaged headlight housing

Damaged headlight housing happens due to wear and tear by long term use or by accidents. This can cause water to escape into housing, leading in decrease of life of headlight assembly.

Damaged bulbs

If any of the two headlights is not working, then check the bulbs in it. I might have got burnt or damaged. If you find both the headlights stop glowing, then be sure that problems are not with the bulbs. It occurs when fuse is blown or there is bad relay or wiring.

Fuse blown off

If the headlight bulbs are in good condition then the fuse might be burnt or blown off. Replacement of the fuse is needed.

Faulty wiring

If the low beam headlight stops glowing then check the fuse. If the fuse is not blown off then the wiring might be be culprit.

The relay of headlight is damaged

The relay supplies power to the headlight when the switch is turned on. These relays are activated by switch.

How to diagnose it?

To fix the headlight issue, first you have to reach the bottom of the problem, you have to point out the exact reason that cause headlight not to glow. There might be an electrical problem like blown fuse or bad wiring or bad relays. There might be a problem in the bulbs. Here are types of headlight issues and tips on how to fix them-

• If you find that one out of two headlights is not glowing, then there might be a faulty bulb in that headlight. Check the bulb if it is faulty or not. If you find it faulty then replace it. If there is no fault in the bulb or you find the headlight still not glowing even after replacing it, then check the fuse, then the wiring and the relays. Check the headlight assembly too, as the cracks in the housing of the assembly would allow water into it and cause damage to various component. If you find it faulty then replacement of the assembly is the only option.
• If both the headlights are not glowing then the problem can be with power and ground. There is very less chance of having bad bulbs because the bulbs usually don’t get damaged in both the headlights at the same time. You can still check the bulbs. You have to check the relays and switch, replace them if you found them faulty.
• If headlights become very dim then there might be foggy lenses in the headlights. Clean the lenses thoroughly till it becomes clear. Check if there is any issue in charging system. If there is any charging system issue then repair the system or replace the battery. Note that if there is charging system issues, then the headlights are most likely to dim in specific circumstances, they don’t remain dim always. If the headlights become dim while idling of engine then there might be a failure of alternator. You have to find out how to fix a faulty alternator.

Fixing headlights is very easy if you have all those tools to test, repair or replace the components that can cause headlights to not work, I have discussed about those components above.

To test the bulb, take a tester put it on the terminals of the bulb while it is connected to battery. You can test whether the current is flowing through the bulb or not by the electric tester. If you have to replace the fuse then replace it with a fuse of same current rating. To test a fuse, take a battery and a voltmeter. Connect both the terminals of the battery and the voltmeter to the fuse. If the voltmeter shows the reading of voltage same or very little difference in voltage rating of the battery then the fuse is damaged. To test the relay, pull it out and shake it near ear. If there is a rattling sound then there is higher chance that the relay is damaged inside.

Conclusion

Here I have told how to test the components in order to know the exact problem that causes headlight issue. Testing can make you sure about the problem and makes it easier to fix the issue. If you have some mechanical skills and the equipment tools to diagnose the issue then you can fix it yourself, it is not a tricky work.

Das European Autohaus is the Houston's leading European Auto Specialists. For years, it has been servicing vehicles from the Spring, Houston, Woodland, Cypress and Tomball, Texas areas. They always strive to provide their customer with quality repair