What is the difference between H4 and H7 car bulbs?
2 Answers
H4 and H7 are types of car bulbs, differing in function, structure, and applicable vehicle models. The specific differences are as follows: 1. Different functions: H4 is generally used for high and low beams; H7 is usually used for low beams. 2. Different structures: H4 consists of three terminals with a base that has two locking tabs; H7 consists of two terminals with a base that has one locking tab. 3. Different applicable models: H4 is suitable for models such as Leopard, Pajero, Jetta, Bora, Sail, etc.; H7 is suitable for models such as Audi A6, Regal, Excelle, Passat, Mazda 3, etc.
I've changed quite a few car bulbs, and the difference between H4 and H7 is quite noticeable. Mainly, the H4 bulb has dual filaments (high and low beam) in a single bulb, allowing direct switching between high and low beams within one headlight housing, which is more convenient with fewer parts to screw during installation. It's suitable for older cars or simpler vehicle designs. However, the H7 has a single filament—one bulb handles only one beam. In newer cars, you need to install two H7 bulbs, one for high beam and one for low beam, offering better brightness but requiring more effort to remove the headlight housing during replacement, which can be quite troublesome. In terms of lifespan, both are prone to burning out, though the H7 has slightly higher power and can illuminate farther, making nighttime driving safer. For regular household use, I’d recommend the H4 for convenience, while newer cars often use H7. The cost difference isn’t significant—neither is too expensive—but always check the car manual for compatibility and avoid random replacements.
