Introduction
A bus head lamp is an essential exterior lighting component installed at the front of a bus, coach or other commercial vehicle. Its primary function is to illuminate the road ahead and help the driver maintain visibility in nighttime and low-light conditions.
Depending on the vehicle design, a head lamp assembly may include several lighting functions, such as:
Different buses may use different head lamp structures, light sources, connectors and mounting systems. Common lighting technologies include halogen, HID and LED.
Understanding the structure and functions of a bus head lamp is useful for bus manufacturers, fleet operators, maintenance companies and commercial vehicle parts distributors when selecting replacement lighting components.
1. What Is a Bus Head Lamp?
A bus head lamp is a front-mounted lighting assembly designed to provide forward illumination and improve the visibility of a commercial vehicle.
Unlike a simple light bulb, a complete head lamp assembly normally combines several components that work together to produce and control the light beam.
A simplified operating process is:
Electrical Power → Light Source → Optical System → Controlled Beam → Road Illumination
The optical system determines how the light is distributed, while the housing protects the internal components from the external environment.
Because buses have different front-end structures, head lamps are often designed for specific vehicle models or applications.
2. Main Functions of a Bus Head Lamp
2.1 Road Illumination
The primary function of the head lamp is to illuminate the road ahead.
Proper forward lighting helps the driver identify:
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Road conditions
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Lane markings
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Obstacles
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Other vehicles
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Pedestrians
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Curves
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Intersections
This is particularly important for buses operating at night or on poorly illuminated roads.
2.2 Low Beam
The low beam provides forward illumination with a controlled beam pattern.
It is commonly used during:
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Night driving
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Urban driving
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Traffic conditions
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Tunnels
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Low-light environments
The optical design is intended to provide useful road illumination while limiting unnecessary glare toward other road users.
2.3 High Beam
The high beam provides a longer and more concentrated forward lighting range than the low beam.
It can help the driver see farther ahead when road and traffic conditions permit its use.
High-beam performance depends on factors such as:
High beams should always be used according to applicable traffic regulations and road conditions.
2.4 Position Light
A position light helps other road users identify the presence and approximate position of the bus.
Depending on the design, the position light may be integrated into the main head lamp assembly.
2.5 Daytime Running Light
Many modern commercial vehicles use Daytime Running Lights (DRLs).
DRLs are designed to improve the visibility of the vehicle during daytime operation.
LEDs are commonly used for this function because they can provide:
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Low power consumption
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Long service life
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Compact design
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Fast response
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Flexible styling
Not every bus head lamp includes a DRL, so the actual configuration depends on the vehicle.
2.6 Turn Signal
Some head lamp assemblies integrate the front turn signal.
The turn signal communicates the driver's intended direction when the bus:
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Turns
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Changes lanes
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Merges
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Enters an intersection
Other bus designs use a separate turn-signal lamp.
3. Main Components of a Bus Head Lamp
A complete bus head lamp generally consists of several major components.
3.1 Housing
The housing is the main structural body of the head lamp.
It supports and protects the internal components and normally contains:
The housing also helps protect the lamp against environmental conditions.
3.2 Outer Lens
The outer lens is the transparent or translucent cover at the front of the lamp.
It protects the internal optical components from:
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Dust
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Water
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Moisture
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Small impacts
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Environmental exposure
The lens also plays a role in controlling or transmitting the light produced by the internal optical system.
3.3 Light Source
The light source generates the actual illumination.
Common technologies include:
Halogen
Halogen bulbs have traditionally been widely used in vehicle lighting.
Advantages include:
HID
High-Intensity Discharge lighting can produce a strong light output and has been used in various vehicle lighting applications.
LED
LED technology is increasingly common in modern commercial vehicles.
Typical advantages include:
The actual light source should match the original head lamp system.
3.4 Reflector
A reflector directs light from the light source toward the desired area.
Its shape and surface design influence:
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Beam distribution
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Light intensity
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Illumination range
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Beam uniformity
Different head lamp designs use different reflector structures.
3.5 Projector
Some modern head lamps use a projector optical system.
A projector can precisely control the light distribution and create a defined beam pattern.
Projector-type designs may be used with different light sources depending on the specific vehicle.
3.6 Electrical Connector
The electrical connector connects the head lamp to the vehicle's wiring system.
It may provide connections for:
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Power
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Ground
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Low beam
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High beam
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Turn signal
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Position light
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DRL
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Other lighting functions
Connector shape and pin configuration are important when replacing a bus head lamp.
3.7 Mounting Brackets
Mounting brackets or fixing points secure the head lamp to the vehicle.
Their location and configuration are usually designed according to the bus body structure.
4. How Does a Bus Head Lamp Work?
The basic working principle is relatively straightforward.
Step 1: Electrical Power
The vehicle electrical system supplies power to the head lamp.
Step 2: Light Source Activation
The selected lighting function activates the corresponding light source.
Step 3: Light Collection
The reflector, projector or other optical components collect and control the generated light.
Step 4: Beam Formation
The optical system creates the required beam pattern.
Step 5: Road Illumination
The controlled light beam illuminates the road ahead.
For an LED head lamp, electronic control components may also be involved in regulating the LED modules.
5. Types of Bus Head Lamps
Bus head lamps can be classified according to light source, optical structure and lighting function.
5.1 Halogen Bus Head Lamp
Halogen head lamps use replaceable halogen bulbs.
They have been widely used on conventional buses and commercial vehicles.
Typical characteristics include:
5.2 HID Bus Head Lamp
HID head lamps use a high-intensity discharge light source.
They can provide high light output and have been used in some higher-specification vehicle lighting systems.
However, HID systems generally involve additional control components compared with basic halogen systems.
5.3 LED Bus Head Lamp
LED head lamps use LED modules as the light source.
They are increasingly used in newer buses because of their efficiency, service life and design flexibility.
An LED head lamp may integrate several functions into a single assembly.
For example:
Low Beam + High Beam + DRL + Position Light + Turn Signal
The exact combination depends on the vehicle.
5.4 Reflector-Type Head Lamp
Reflector-type lamps use a reflector to distribute light from the light source.
They can have relatively simple optical structures and are used across different commercial vehicle applications.
5.5 Projector-Type Head Lamp
Projector-type lamps use a lens and optical system to create a more controlled beam pattern.
They can provide a clearly defined illumination area when properly designed and installed.
5.6 Integrated LED Head Lamp
Some modern bus head lamps combine several lighting functions in a single housing.
This can include:
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Low beam
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High beam
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DRL
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Position light
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Turn signal
This type of design can help simplify the front lighting layout and create a more integrated appearance.
6. Bus Head Lamp vs Passenger Car Head Lamp
Although both are designed for road illumination, bus head lamps can have different requirements from passenger-car head lamps.
| Feature |
Bus Head Lamp |
Passenger Car Head Lamp |
| Vehicle Size |
Larger commercial vehicle |
Smaller vehicle |
| Housing |
Often vehicle-specific |
Vehicle-specific |
| Mounting |
Designed for bus body structure |
Designed for car body structure |
| Electrical System |
Often 24V on many buses |
Often 12V |
| Operating Hours |
Frequently high |
Depends on usage |
| Vibration |
Commercial vehicle environment |
Passenger vehicle environment |
| Lighting Configuration |
Application-specific |
Application-specific |
| Replacement |
Often model-specific |
Usually model-specific |
The voltage shown in the table is only a general reference. The actual electrical specification should always be confirmed for the specific vehicle.
7. Applications of Bus Head Lamps
Bus head lamps are used across many types of commercial vehicles.
7.1 City Buses
City buses operate frequently in urban environments and may require reliable front lighting for:
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Night routes
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Early-morning operation
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Tunnels
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Poor-weather conditions
7.2 Intercity Buses
Intercity buses often operate over longer distances and may spend significant time on highways.
Reliable forward illumination is particularly important during nighttime operation.
7.3 Coaches
Tourist and long-distance coaches may use larger or more integrated head lamp assemblies.
Depending on the vehicle design, LED lighting can be used for multiple front lighting functions.
7.4 Electric Buses
Electric buses also require head lamps, but their electrical architecture can differ from conventional buses.
The lighting system generally operates from the vehicle's low-voltage electrical system rather than directly from the high-voltage traction battery.
Depending on the vehicle architecture, the low-voltage system may be supplied through a DC-DC converter.
Therefore, the actual head lamp voltage must be confirmed before replacement.
7.5 School and Shuttle Buses
School buses and shuttle buses can use vehicle-specific head lamps designed around their body and front-end structures.
The exact lighting configuration varies by vehicle and applicable regulations.
7.6 Special-Purpose Commercial Vehicles
Head lamp assemblies can also be found on:
8. Why Is Head Lamp Design Important for Buses?
Buses have several characteristics that influence head lamp design.
Large Vehicle Dimensions
The lamp must integrate with a relatively large front body structure.
Long Operating Hours
Fleet buses may operate for many hours per day.
Frequent Starts and Stops
Urban buses can experience frequent operating cycles.
Different Road Conditions
Buses may operate in cities, highways, rural roads and other environments.
Maintenance Requirements
Fleet operators need lighting components that can be inspected, serviced and replaced efficiently.
For these reasons, head lamp selection should consider both lighting performance and vehicle compatibility.
9. Common Bus Head Lamp Specifications
When identifying or purchasing a bus head lamp, several specifications should be checked.
| Specification |
What to Check |
| Vehicle Application |
Bus brand and model |
| Light Source |
Halogen, HID or LED |
| Voltage |
Vehicle-specific rated voltage |
| Beam Type |
Low beam, high beam or combined |
| Lighting Functions |
DRL, position light, turn signal, etc. |
| Connector |
Shape and pin configuration |
| Housing |
Material and structure |
| Dimensions |
Length, width and height |
| Mounting |
Brackets and mounting holes |
| Optical Type |
Reflector or projector |
| Left/Right Side |
Driver-side or passenger-side application |
| Certification |
Applicable market requirements |
The exact specification should be confirmed against the original vehicle and lamp.
10. Left-Hand and Right-Hand Head Lamps
Bus head lamps are commonly available as left-hand and right-hand versions.
The two sides may have differences in:
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Housing shape
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Mounting points
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Beam pattern
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Connector position
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Optical configuration
When ordering a replacement, always specify which side is required.
For example:
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Left Head Lamp
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Right Head Lamp
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Pair of Head Lamps
Do not assume that the left and right lamps are interchangeable.
11. How to Identify a Bus Head Lamp
If the original part number is available, it should be used as one of the main identification references.
If the part number is unavailable, collect:
Vehicle Information
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Bus brand
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Bus model
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Production year
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Vehicle type
Product Information
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Front photo
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Rear photo
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Lamp dimensions
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Original markings
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Manufacturer information
Electrical Information
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Connector photo
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Pin count
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Rated voltage
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Bulb or LED type
Installation Information
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Mounting-hole position
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Bracket structure
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Left or right side
The more information provided, the easier it is to identify a compatible replacement.
12. Common Differences Between Bus Head Lamp Models
Different head lamps may look similar but have important differences.
They may vary in:
Therefore, visual similarity alone should not be used to confirm compatibility.
13. Maintenance of Bus Head Lamps
Regular inspection can help maintain proper lighting performance.
Check the following:
Lens Condition
Look for:
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Cracks
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Scratches
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Cloudiness
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Water accumulation
Electrical Connections
Inspect:
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Connectors
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Wiring
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Terminals
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Ground connections
Mounting
Make sure the lamp is securely mounted and does not move excessively.
Light Output
Check whether:
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Low beam works
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High beam works
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Turn signal works
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Position light works
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DRL works, if equipped
Condensation
Small amounts of temporary condensation may occur in some lamp designs due to temperature changes, but persistent water accumulation should be investigated.
14. Common Reasons for Replacing a Bus Head Lamp
A head lamp may need replacement when:
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Housing is cracked
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Lens is severely damaged
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Internal components have failed
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Light output is abnormal
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Mounting points are broken
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Water intrusion has caused damage
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Electrical connections are damaged
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The complete assembly is no longer economical to repair
For some lamp designs, individual bulbs or modules can be replaced. For others, replacing the complete assembly may be more practical.
15. Bus Head Lamp Replacement Considerations
Before ordering a replacement, confirm:
Vehicle Model + Lamp Side + Part Number + Voltage + Connector + Dimensions + Lighting Functions
For fleet purchasing, also consider:
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Required quantity
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Spare-parts demand
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Delivery time
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Packaging
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Replacement availability
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OEM/ODM requirements
For international sourcing, clear product identification can help reduce the risk of receiving an incompatible lamp.
Frequently Asked Questions
What is a bus head lamp?
A bus head lamp is a front-mounted lighting assembly that provides forward illumination and may integrate functions such as low beam, high beam, position light, DRL and turn signal.
What types of bus head lamps are available?
Common types include halogen, HID and LED head lamps. They can also be classified as reflector-type, projector-type and integrated multi-function designs.
Are LED head lamps better than halogen head lamps?
LED and halogen technologies have different characteristics. LED systems can offer long service life, efficient operation and flexible design, while halogen systems are simple and widely established. The appropriate choice depends on the vehicle application and original lighting system.
Are bus head lamps usually 24V?
Many buses use 24V electrical systems, but this is not universal. The actual rated voltage must be confirmed for the specific bus and head lamp.
Can a passenger-car head lamp be installed on a bus?
Not necessarily. Physical dimensions, mounting points, electrical specifications, beam pattern and connector configuration may be different.
Does a bus head lamp include the turn signal?
Some assemblies include the turn signal, while others use a separate lamp. The configuration depends on the vehicle design.
What is the difference between a reflector and projector head lamp?
A reflector uses a reflective optical structure to distribute light, while a projector uses a lens-based optical system to control the beam more precisely.
How do I identify the correct bus head lamp?
Start with the bus brand, exact model, production year and original part number. Product photos, connector photos, dimensions and left/right-side information can also help confirm the correct replacement.
Can the left and right bus head lamps be used interchangeably?
Usually not. Left and right head lamps can have different housings, mounting structures and beam configurations.
How long does a bus head lamp last?
Service life depends on the light source, operating environment, product design and usage conditions. LED systems can generally have a long light-source service life, but the complete assembly can still be affected by electronics, connectors, housing and environmental conditions.
Conclusion
A bus head lamp is more than a simple lighting component. It combines a light source, optical system, housing, electrical connections and mounting structure to provide controlled forward illumination and other vehicle lighting functions.
Common types include:
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Halogen Head Lamps
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HID Head Lamps
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LED Head Lamps
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Reflector-Type Head Lamps
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Projector-Type Head Lamps
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Integrated Multi-Function Head Lamps
For city buses, coaches, electric buses, shuttle buses and other commercial vehicles, the correct head lamp should match the vehicle's electrical system, physical structure and required lighting functions.
When sourcing a replacement, the most useful identification information is:
Bus Model + Production Year + Original Part Number + Left/Right Side + Connector + Dimensions + Product Photos
For bus manufacturers, fleet operators and commercial vehicle parts distributors, accurate product matching helps reduce installation problems and improve replacement efficiency.
Looking for a bus head lamp or other commercial vehicle lighting components?
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Send us your original head lamp photo, part number, bus model and required quantity to discuss a suitable replacement solution.
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