Collection: BX8.4d / BX8.5d Bulbs

The BX8.4d base: a variant of the B8.5d

The BX in BX8.4d and BX8.5d denotes a variant of the B8.x base with an offset contact (axial) – different from the centered contact of the standard B8.5d. This offset prevents the bulb from being installed incorrectly, which is important for certain signaling applications where the filament direction matters.

These bases are found on:

• BMW 3 Series (E36, E46) and 5 Series (E39, E60) – dashboard indicator lights
• Mercedes C-Class (W202, W203) and E-Class (W210, W211)
• Some VAG (Audi A4 B5/B6) in specific applications
• Volvo S60, V70 – in certain configurations

BX8.4d vs BX8.5d: what's the difference?

The number indicates the length of the base in millimeters:

• BX8.4d – 8.4 mm in length
• BX8.5d – 8.5 mm in length

A very small difference (0.1 mm) but not interchangeable on all vehicles – some sockets only accept the exact length. Always check the precise measurement on the original bulb.

BX vs B: offset or centered contact

• B8.5d – centered contact (pin in the middle)
• BX8.5d – axially offset contact (off-center pin)

This difference prevents cross-mounting – a BX8.5d will not fit into a B8.5d holder and vice versa. The exact mark is crucial when ordering.

LED BX8.4d / BX8.5d

Replacement LEDs exist with the same contact configuration. For recent BMW and Mercedes with advanced CAN-Bus, it is essential to choose a canbus version to avoid dashboard errors.