Volvo 740 Headlight Bulb Size

Additional Notes

• The Volvo 740 uses two distinct headlight technologies across its production run. The 1985-1989 model years rely on sealed beam units, while the 1990-1992 model years use a replaceable halogen bulb system.
• The 9004 bulb, fitted to the 1990-1992 Volvo 740 for both high and low beam functions, is a dual-filament halogen unit with a P29t base rated at 12V and 65W on the high beam filament and 45W on the low beam filament. A single bulb serves both functions within one housing.
• The H4651, H4652, and H4656 are all 4x6-inch rectangular sealed beam units operating at 12V. In a sealed beam design, the lens, reflector, and filament are fused into one unit, meaning the entire assembly is replaced rather than an internal bulb.
• The H4652 is a variant of the H4651. Both share the same 4x6-inch rectangular sealed beam form, though they are not interchangeable with the H4656 despite the shared physical format.
• On the 1985-1989 Volvo 740, the high beam position uses the H4651 across all five years, while the low beam position alternates between H4652 and H4656 depending on the specific year, making year-by-year verification necessary before replacement.
• The 1986 and 1989 low beam positions specify the H4656, whereas 1985, 1987, and 1988 specify the H4652. Substituting one sealed beam type for the other without confirming the correct designation risks an incorrect fitment.
• The transition from sealed beam units to the 9004 halogen system in 1990 also represents a shift from a non-serviceable assembly to a housing where only the internal bulb requires replacement during a failure.
• All bulb types listed across the Volvo 740 headlight specifications conform to ANSI standards applicable in the United States and Canada, indicating regulatory compliance for those markets.