Prevost High Decker headlight bulb sizes include H9, 9004, and H4651 for high beam applications and H9, D2S, and 9004 for low beam configurations. The replacement chart covers 1988 through 2019 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H9 bulb is the most widely specified type across the Prevost High Decker headlight data, appearing in both high beam and low beam positions for model years 2005-2019. It is a halogen bulb operating at 65 watts with a PGJ19-5 base, designed for single-filament use in projector or reflector housings.
The 9004 bulb type is specified for both high beam and low beam positions on the Prevost High Decker from 1990-2003. It is a dual-filament halogen bulb with an HB1 designation, meaning a single unit handles both beam functions through two separate filaments within one envelope.
Because the 9004 bulb serves both high and low beam functions through its dual-filament construction, it is not interchangeable with the H9, which is a single-filament bulb. Substituting one for the other would result in incorrect or non-functional beam output.
For model years 2005-2019, the Prevost High Decker low beam position accommodates two distinct bulb types depending on headlamp system: the H9 for halogen capsule headlamps and the D2S for HID headlamps. These two systems are not interchangeable, as HID and halogen technologies require different ballasts and housing configurations.
The D2S is a high-intensity discharge bulb that operates through an electrical arc between two electrodes rather than a heated filament. It requires a compatible HID ballast and igniter, making it incompatible with standard halogen wiring without additional components.
The 1990 Prevost High Decker high beam position lists two bulb sizes: the 9004 and the H4651. This indicates that two different headlamp configurations were available for that model year, each requiring a different bulb.
The H4651 and H4656 bulb types appear in the 1988-1990 high beam data and the 1988-1989 low beam data. Both are sealed-beam rectangular halogen units, a format that was common before the widespread adoption of replaceable-bulb composite headlamp assemblies.
The H4651 and H4656 differ in their light output characteristics, with the H4656 typically used for low beam and the H4651 for high beam applications. The 1988-1989 specifications reflect this split, listing H4656 for low beam and both H4656 and H4651 for high beam in those years.
The high beam position for model years 2005-2019 specifies only the H9, with no HID variant listed, unlike the low beam position for the same years. This means the high beam circuit on those vehicles is halogen-only regardless of whether the low beam system is halogen or HID.
The absence of a 2004 and 2009 entry across all positions in the specifications means no bulb data is attributed to those model years for the Prevost High Decker in this dataset.