The 3175 bulb is a 31 mm festoon-style miniature interior automotive bulb commonly installed in vanity mirror lights, map lights, glove-box lamps, dome lights, license-plate lights, and footwell accent fixtures. It uses bullet-style festoon clip ends that seat into spring-loaded 31 mm festoon sockets, making exact 31 mm length compatibility critical for electrical contact and mechanical stability in tight housings such as sun visors and console lids.
- Voltage: 12 V DC automotive system
- Power draw: ~0.5–2 W (vs 3–5 W halogen)
- LED types: SMD 2835 / 5050 or COB
- Brightness: ~60–200 lumens
- Polarity: directional unless non-polar circuitry
- Heat: near-zero vs filament bulbs
Some variants include CANbus resistor circuitry, useful when installed in license-plate or BCM-monitored circuits to prevent bulb-out warnings or flicker.
This Underground Lighting collection includes 3175 LED replacement bulbs, upgrading the original 3–5 W incandescent festoon to a 12 V solid-state LED system consuming only ~0.5–2 W. Light is produced via surface-mount diode (SMD 2835 / 5050) or COB LED arrays, delivering ~60–200 lumens depending on chip density and optical spread. Compared with filament bulbs, 3175 LED festoons produce higher brightness, dramatically lower heat, and a 20,000–50,000-hour lifespan.
The collection contains:
- 3175 31 mm 6-SMD Festoon LED Bulb
Higher-output 31 mm festoon LED using multi-chip SMD layout for dome, plate, and glove-box lighting where more illumination is required.
- 3175 31 mm 4-SMD Festoon LED Bulb
Moderate-output compact festoon LED optimized for vanity mirrors, map lights, and low-clearance housings requiring controlled brightness.
Available colors: white, blue, red, green for interior styling; white (5000–6000 K) recommended for license-plate positions to meet road-use regulations.
Primary Functional Applications & Fitment
Vanity Mirror Light (Sun Visor)
Compact directional lighting in visor housings with very limited clearance. 31 mm festoon LEDs provide brighter reflection visibility with minimal heat near fabric and plastic trim.
Map / Reading Light
Overhead personal illumination requiring soft-focus beam. Lower-lumen or diffused SMD/COB LEDs prevent glare in clear lenses.
Glove Box / Console Light
Small compartment lighting improving nighttime access. LED festoon increases clarity and reduces heat in enclosed housings.
Dome / Cabin Accent Light
Secondary interior illumination zones using miniature festoons. LED upgrade enhances overall cabin brightness.
Footwell / Ambient Lighting
Under-dash or accent lighting using colored LEDs (blue/red/green) for styling and visibility.
License Plate Light
Exterior rear tag illumination requiring white LED output (~5000–6000 K) for compliance with DOT/ECE lighting standards.
Exact Size & Cross-Compatibility Clarification
Festoon bulbs are strictly length-specific:
- 3175 = 31 mm
- 3425 = 36 mm
- 6418 = 38 mm
- 6411 / 578 = 42 mm
Even a 2–3 mm mismatch prevents secure seating or causes flicker in festoon clips. 3175 is also not interchangeable with wedge bulbs (194/168/2825) due to a completely different base design.
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