3 Notes When Customizing, Repairing and Changing Car Lights Should Refer

Car Light Level
Latest update date: February 08, 05

Car lights are likened to the eyes of a car. They not only have the effect of increasing visibility for the driver but also have an aesthetic meaning, showing the spirit of the car.

AAA (American Automobile Association): AAA research shows that headlights adjusted higher than necessary can dazzle oncoming drivers, reduce visibility and increase the risk of nighttime accidents. Research shows that adjusting the lamp 1° higher can increase the glare area by up to 6m.

Adjusting car lights also involves installation, adjustment and maintenance. To ensure that the lamp is installed correctly and operates effectively, it is necessary to comply with the manufacturer's instructions and regulations and local laws. Adjusting lighting configurations and regular checks help ensure that lights are working properly and are not disturbing others on the road.

If you want to repair or upgrade car lights, don't skip the following article. Thanh Phong Auto will share important notes when intending to repair, customize, and make lights for your pet.

Car Light Level
Car Light Level & Things to Know

Common Errors in Car Headlights and Underbody Lights

1. Common faults in headlights

Headlights often have problems due to the following errors:

  • Dim headlight light: due to not cleaning the bulbs regularly.
  • One side light does not light: due to a broken wire on one side connected to the headlight.
  • The headlight light is flickering: due to a loose or short circuit in the neck of the light switch.
  • Headlight does not light: due to sudden increase in generator voltage or lamp operation for too long.

2. Common errors in car underbody lights

Car underbody lights often have problems due to:

  • Car underbody lights flashing: lamp condition degrades when used for a long time.
  • Car underbody lights are weak: because the diffuser of the underbody lights has a lot of dirt.
  • The car's underbody light does not light: the generator's voltage is high and has been operating for a long time.

Should You Adjust or Replace Car Light Bulbs?

Adjusting, repairing or changing car light bulbs can depend on many different factors. Here are some factors to consider when deciding whether to adjust, repair or replace your car's light bulbs:

  • Local laws: You should check your area's regulations regarding adjusting, repairing or changing car light bulbs. Some localities have strict regulations on changing vehicle lighting systems to ensure compliance with traffic and safety standards.
  • Quality and performance: At times, drivers may want to upgrade their car bulbs to improve lighting performance. However, attention should be paid to the quality and performance of replacement bulbs. You should choose good quality bulbs that comply with standards and are highly rated to ensure that you have good lighting and do not affect others on the road.
  • Technical knowledge and experience: Adjusting, repairing or changing car light bulbs often requires technical knowledge and experience. If you do not have the necessary skills and experience, you should find a shop or professional to do this job. This ensures that the work is done properly and does not harm the car's electrical system and chassis.
  • Warranties and guarantees: If you decide to purchase replacement bulbs or use a repair service, consider warranties and guarantees. This gives you peace of mind about the quality and performance of the product or service you choose.
Car Light Level Regulations
Should You Adjust/Replace Car Light Bulbs?

Issues to Pay Attention to When Repairing Lights, Tuning - Car Lights

1. Check the status of lighting system before repairing

Before repairing the lights, tuning - making car lights, please check the light bulb system, see if they have the phenomenon of burning balls, broken filaments or not. Then identify the cause and provide timely treatment according to the need. Specifically, in the case of a headlight bulb burn, you should replace the bulb with a new one to ensure the safety of everyone during the trip.

2. Comply with the steps of checking and repairing lights, tuning - making car lights

Steps to check car lights you need to follow:

  • Check the operation of the headlights.
  • Check tail lights, fog lights, brake lights, especially at night or in a dark garage for best results.

After the inspection is complete, you should determine the cause of the failure of the lighting system. In the case of replacing car headlight bulbs, first find the position of the lamp holder. Next is to remove the lamp holder and the burned out headlight bulb. Finally, insert the new headlight bulb into the lampholder and reassemble the removed parts.

You should install the bulb in the correct slot, do not let the rubber gasket stick out. Besides, it is recommended to wipe your hands clean before installation to limit grease from sticking to the glossy surface.

If you do not have experience and techniques in repairing car lights, the best option is to take the car to the garage. A reputable garage will have full tools, specialized machines as well as experienced car repairmen. They will quickly detect the cause of the failure of the vehicle light system, thereby offering a timely treatment plan and repairing it in the fastest time.

3. Note to fix, customize - car lights do not violate the law

Many car owners often customize – add headlights, fog lights, especially led bar lights (a bar with many led lights) to make their car “cooler”. The price of these lights is only from a few hundred to a few million dong, with specialized types for off-road people going off-road, it can be up to several tens of millions.

The installation of light equipment is quite simple, so many people often manually upgrade their cars according to their needs and preferences. However, adding more lights can break the law and expose car owners to the following problems:

  • Clause 2 – Article 55 of the Law on Road Traffic: Vehicle owners are not allowed to change the vehicle's structure, system, and overall components with the manufacturing/renovating design approved by a competent authority.
  • Clause 3 – Article 16 of Decree 100/2019/ND-CP: Driving a car with additional lights in front, back, on the roof, under one or both sides of the vehicle will be fined from 800 to 1 million dong. At the same time, the driving license will be revoked from 1 to 3 months.

Document No. 6688/DKVN-VAR of the Vietnam Registry Department: Installing additional lights for cars in violation of regulations will be refused by the registration units for inspection.

Not only that, high light intensity for cars (especially led bar lights) can also cause glare, potentially causing many traffic accidents.

Therefore, if you want to upgrade your car's lights, you absolutely must not change the original design and design of the manufacturer yourself. It is best to go to a reputable garage to be consulted by a technical staff for a suitable modding plan, ensuring both aesthetics and class, while complying with the provisions of the law.

Prestigious Car Light Garage Hcm
Precautions when adjusting/replacing car light bulbs?

Frequently Asked Questions When Adjusting Car Lights

1. What is the difference between headlights and underbody lights?

High beams have a longer range, often used when driving on the highway at night. Low beam lights have a closer range, used when driving in the city or when there are vehicles coming in the opposite direction to avoid glare.

2. How to periodically clean and maintain headlights and underbody lights?

Cleaning/maintaining headlights and underbody lights should ensure:

  • Clean the lamp glass with a soft cloth and specialized glass cleaner every 2-3 months.
  • Check electrical wire connections and switch collars every 6 months.
  • Replace the light bulb with a new one if it dims or burns out after 1-2 years of use or 20.000-30.000 km.

You can refer to some Causes of broken car headlights Helps you find the fastest and safest solution.

3. What type of light bulb should I choose when replacing headlights and underbody lights?

You should choose genuine, high-quality light bulbs such as halogen, xenon or LED bulbs. Poor quality light bulbs can quickly fail, causing glare or fire. Consult an auto mechanic to choose the right light bulb for your vehicle.

4. How to adjust the beam angle of the headlights?

Adjusting the beam angle of headlights should note:

  • Park on a flat surface, 5m away from the wall.
  • Turn on the headlights, adjust the screw so that the center of the light beam is 10cm above the ground.
  • Adjust the horizontal screw so that the center of the light beam is 5-10cm from the center line.

5. If there is a problem with headlights or underbody lights, how to handle it?

How to handle problems with headlights and underbody lights:

  • Check fuses, broken or shorted wires.
  • Check switches and light relays.
  • Replace the light bulb with a new one if the old one is burned out.
  • Take the car to a garage if you can't fix it yourself.

6. What are the advantages and disadvantages of LED lights for cars?


  • White light, brighter than the original light.
  • Long lifespan, energy saving.
  • Beautiful design, increases the aesthetics of the car.


  • The price is higher than regular lights.
  • Needs more complicated installation and adjustment.
  • Can cause glare if not adjusted properly.
  • It may be against the law to change the function of the light.

7. What are the legal regulations regarding car lighting?

Car lighting levels need to comply with the following regulations:

  • Do not change the design or function of the lamp compared to the manufacturer's original design.
  • Do not install additional lights at the front, rear, on the roof, or under the vehicle.
  • If violated, you can be fined 800.000-1.000.000 VND, have your license revoked for 1-3 months, and be denied registration.

Additionally, you can read the article immediately regulate penalties for arbitrarily modifying cars details, updated according to the latest provisions of law.

8. Where should I get reputable and quality car lights?

You should look for reputable and experienced garages and auto light shops. Avoid buying poor quality lights or installing them incorrectly. Refer to user reviews and ratings before choosing a lighting location.

9. Does car light brightness affect the car warranty?

Adjusting car lights can void the warranty of some related items such as the electrical system. However, if the lights are installed at the company's authorized garages, the warranty may still be covered. You should consult the dealer or car company before adjusting the lights.

10. Should headlights and underbody lights be replaced in pairs?

Headlights and underbody lights should be replaced in pairs to ensure uniform brightness and color for both sides of the lights. Replacing one side of the light can cause an imbalance or loss of aesthetics for the vehicle. If only 2 bulb is broken, you can replace only 1 side.

Above are Thanh Phong Auto's shares about the notes when repairing lights, tuning - making car lights. Thereby, to increase visibility and ensure safety when participating in traffic, you should take your car to a reputable garage. We believe that with modern machinery and tools and skilled technicians, the car's lighting system will work well, stably and aesthetically.

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