Can I replace a headlight bulb myself?
In the event of certain defects or malfunctions, it is not always necessary to go to the workshop immediately. Depending on the vehicle, various problems can also be fixed by the vehicle owner. For many cars, this is the case if a light bulb has failed. In the following, you will therefore receive detailed do-it-yourself instructions on how to change bulbs on your car. However, this can no longer be done so easily on every vehicle.
Bulbs and lights on the car
First, a distinction must be made between the lighting technology and the lights on the vehicle, where a light bulb is to be replaced.
In the meantime, the following technical lighting products can be distinguished on the automobile:
- Incandescent bulbs (with one filament).
- Xenon and bi-xenon (gas discharge lamps).
- LED illuminants.
1. Changing Xenon Bulbs
Xenon is used on motor vehicles for the high beam (bi-xenon) and low beam of the headlights. It has slowly replaced halogen bulbs starting in the 1990s, but still represents an extra charge on many vehicle models. Therefore, a particular model does not necessarily have to have xenon headlights.
With xenon, the legislator prescribes certain features. For example, headlamp leveling must change automatically and continuously. In some cases, headlight cleaning systems are also prescribed. In order for the gas in the xenon glass bulb to ignite, an electronic ballast (EB) is required.
In the process, the electronic ballast provides up to 25,000 volts in the short term for igniting the gas contained in the burner. So there is basically a great danger to life. For this reason alone, defective xenon lamps should not be replaced by a layman. In addition, there does not necessarily have to be a defect in the burner. The ballast or the cable connection can also be damaged.
2. Changing LED Bulbs
In the case of LED bulbs, a distinction must now be made between LEDs that are modeled on incandescent bulbs and are built on corresponding lamp bases as for the incandescent bulbs in question. These LED bulbs can basically be replaced themselves. They are then changed like normal light bulbs, which is why the DIY instructions for changing light bulbs can be used.
The situation is different with modern LED lights and headlights of the latest generations. Here, the LEDs are permanently integrated into the taillight or headlight. This means that, as a rule, the entire headlight or the rear light in question must be completely replaced here. Here, too, the route should lead to a certified specialist workshop.
Change light bulbs on the car yourself
When it comes to light bulbs, it is necessary to first distinguish between the most important bulbs:
- Headlights bulbs- headlights and fog lights.
- Blinker lights front Bulb- blinker lights front.
- Sidelights bulb- sidelights (position lights).
- Rear lights Bulb rear lights, possibly with separate reversing light and/or rear fog light.
- Bulbs on license plate lighting- bulbs on license plate lighting.
- Interior lighting Bulbs- Interior lighting.
Headlight bulb replacement
The right halogen bulbs
Analogous so systems with four headlights are also possible compact headlights, which can combine different lights including fog lights. Many Mercedes headlights are an example of this. In addition, H7 headlights are equipped with a clear lens and H4 with a textured lens. However, if you don’t know what bulbs you need for your vehicle’s headlights, you can also check your vehicle’s spec sheet or service book.
Another identifying feature of the different halogen bulbs is the different bulb bases.
- H1 to H3 have a short piece of cable, at the end of which there is a plug of a certain shape, depending on the H type.
- H5 and H6 have different-sized base diameters but are hardly used on cars anyway.
- H7 and H4 differ in that different numbers of webs protrude from the socket.
Special features and important tips for H4 bulbs
Tips for H4 bulbs
In the H4 bulb, there are three such ridges, which are arranged at reasonably equal intervals. Although these bars are of different widths and thus actually fit into the bulb socket in only one position, they can also be inserted incorrectly with slight force. Therefore, we would like to give you a little mnemonic for the still common H4 bulbs: You can see the filaments in the glass bulb on a reflector, which is bulged out at the front like a small pan. You must be able to spit (mentally) into this pan when installing, then, the H4 bulb is inserted the right way around.
Also, before the actual bulb replacement instructions, we have another important note:
Handle the bulbs by the base only, but never by the glass. There is always some grease, moisture, and dirt on our hands and fingers. The grease and moisture heat up, can destroy the bulb. Very often, the fingerprint from the glass bulb leads to a fogging light disk (the glass of the headlight). So new bulbs and especially halogen lamps because of the high temperatures really always touch only the metal base to avoid fogged headlights.
Changing the bulbs on the headlight yourself
Unfortunately, we may have some bad news for you here as well. Not with every vehicle model the change of the bulbs is still done within a few seconds or minutes. Conventionally, there is a hand-sized cap on the back of the headlight that is screwed on. This cap is removed to reveal the bulb and bulb socket. However, on some modern vehicles, changing the bulb is no longer as simple.
It may be necessary to remove the entire headlight, and on some models also the radiator grille, the wheel housing trim, or even the front trim. However, some manufacturers are making efforts to simplify bulb replacement again on some models in response to fierce customer criticism.
- Simply open the hood and take a look at the back of the headlight. If it is easy to open, there is nothing to stop you from changing the bulbs.
- For other models, you need to contact the vehicle manufacturer to find out whether and how to change the bulb. Numerous specialist forums on specific models on the Internet can help. Other vehicle owners often post very detailed instructions on how to do it yourself.
How to change the light bulb on the headlight of the car
- First, buy the appropriate bulb, for example, H7 or H4 bulbs.
- Turn off the ignition. It is best to remove the ignition key completely.
Then open the hood.
- Remove the car headlight.
- On the back of the headlight, you will now see a gray or black round cap that is screwed on. This is about the size of your hand.
- If the cap is very tight, use a towel and gloves to apply more force.
- Discover bulb base.
- Once you have removed the cap, you are free to see the bottom of the bulb base. Pull the connector off the lamp base. You will now see a wire bracket, which mostly holds the lamp base in the socket on both sides. If you follow the bow, it is hooked into a fold at the back of the lamp. To unhook it, press the bracket down slightly at this position and bend both ends together slightly.
- Now the bracket can be folded down. The bulb may already fall out of the socket.
- Remove the broken bulb
- Now remove the broken bulb, take the new halogen bulb out of the packaging by the base and insert it according to the lugs or webs. For H4 bulbs, remember our tip with the reflector socket.
- Now hang the metal bracket back in place, plug the cable connector onto the bulb and close the headlight cap.
- Finally, check the low beam and high beam.
- In addition, drive close to a wall and check the light pattern of the low beam. Especially if they are different heights or look uneven, this is a reason to adjust the headlights. To do this, you need to drive to a garage or an appropriately equipped service station. Often this service is offered free of charge.
How to change other light bulbs on the car yourself
1. Change parking light by yourself
The parking light is often located at a different position on the reflector and is often more difficult to reach.
Check the exact position with the parking light switched on using the still working parking light on the other side.
2. Change side and front turn signal bulbs yourself
This can be difficult. On some models, the turn signal lenses can be unscrewed from the outside. In most cases, however, the turn signals are hooked in with a spring in a very complicated way, so that the workshop of your choice has to be consulted.
3. Change the bulbs on the rear lights yourself.
- Changing the bulbs on the taillights is done from the inside of the trunk of most cars. Behind the taillights is the cover hung or screwed into the interior trim
- To remove this, the end cap can be removed from the light. You will now see a kind of circuit board, the lamp holder. This is either screwed into the tail light or just inserted or clamped in place. Remove it according to the manufacturer’s workshop manual.
- Now you can replace the individual bulbs. On some models, the plastic taillight lens must be unscrewed from the outside so that you can change the bulbs.
- Watch out for bulbs with two filaments.
All these bulbs are removed by pushing them down slightly from the top (glass bulb side) to the socket side, and then turning them sideways and letting go. This is because these bulbs also have lugs on the side where the lamp bases are hooked. Depending on the lamp bases, there are different numbers of lugs also positioned differently.
For bulbs with two filaments, you need to make sure that you insert the bulb the right way around. Because it is a bulb for low beam (5 W) and brake light (21 W).
If you insert the bulb the wrong way around, the two contacts on the lamp socket and thus the brake light and tail light are reversed.
Ensure correct fit of rubber seals between lamp glass and lamp holder or rear sealing cap.
4. Replacing bulbs inside the car and on the license plate light
- On some models, the license plate is illuminated by the tail light. Others have special license plate lights. These are simply screwed on. So are most of the lights inside the car.
- The bulbs (soffits) used here look like glass fuses. They are simply levered up carefully with a screwdriver.
- Then the new festoon is just pushed in until it snaps into place.