Auto Headlight Light Sensor Module – MK4 B5 9N Replacement
Auto Headlight Light Sensor Module – MK4 B5 9N Replacement
Auto Headlight Light Sensor Control Module for MK4, B5 & 9N
Upgrade your vehicle's lighting system with this premium aftermarket Auto Headlight Light Sensor Control Module. Designed as a direct plug-and-play replacement, this module automatically manages your headlights based on ambient light levels — so you never have to worry about forgetting to switch them on or off. Perfect for MK4, B5/B5.5, and 9N/9N3 platform vehicles, it matches original factory specifications for a seamless, hassle-free fit.
Key Features
- Automatic On/Off: Headlights activate or deactivate instantly when ambient brightness drops below or rises above the set threshold.
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Three Lighting Modes:
- 🚇 Tunnel Mode — Reaction time: 1 second
- 🌥️ Normal Mode — Reaction time: 3 seconds
- 🌅 Delay Mode — Reaction time: 5 seconds
- Battery Protection: Lights turn off automatically before engine start; turn on automatically 3 seconds after engine start.
- Direct OEM Replacement: Replaces part numbers 1C0941531, 3BD941531, 3BD941531A for a factory-perfect match.
- Durable ABS Plastic Housing: Robust, crack-resistant construction built to last.
- Easy Installation: Direct plug-in replacement — no cutting or splicing required.
Specifications
| Condition | 100% Brand New |
| Material | ABS Plastic |
| Color | Black |
| Dimensions | 10 × 6 cm / 3.9 × 2.4 in |
| Cable Length | 112 cm / 44.1 in |
| Package Weight | approx. 197 g / 6.9 oz |
| OEM Part Numbers | 1C0941531, 3BD941531, 3BD941531A |
| Country of Origin | Made in Mainland China |
Vehicle Compatibility
- MK4 (1999–2004)
- B5 / B5.5 (1998–2005)
- 9N / 9N3 (1999–2001)
- SEAT I (7V8, 7V9) — 1781–2792 cc, 90–204 PS
- SEAT I Hatchback (6Y2) — 996–1984 cc, 50–130 PS
- SEAT I Hatchback (1U2) — 1390–1984 cc, 60–180 PS
⚠️ Compatibility is provided for reference only. Please verify the OEM part number against your original part before ordering.
Installation Notes
- Disconnect the vehicle battery's negative terminal and set the switch to position 0 before disassembling or assembling to prevent short circuits.
- Attach the included black adhesive sensor probe near the rearview mirror base on the front windscreen — avoid areas blocked by wipers or sunshades, and do not place it inside the dashboard.
- Route the wiring harness along the instrument panel gap, away from air conditioning outlets and high-temperature pipelines.
- Insert the original car bulb plug directly without force — do not pry the snap ring. Leave 5 cm of slack in the harness.
What's in the Box
- 1 × Headlight Switch with Light Sensor Module
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Learn more: FuelEconomy.gov driving efficiency guidance
Frequently Asked Questions
Q: Which vehicles is this headlight light sensor control module compatible with?
A: This module is designed to fit MK4 (1999–2004), B5/B5.5 (1998–2005), and 9N/9N3 (1999–2001) platform vehicles, as well as select SEAT models. Always confirm compatibility by matching the OEM part numbers (1C0941531, 3BD941531, or 3BD941531A) to your original part before purchasing.
Q: Do I need to cut or modify any wiring to install this module?
A: No. This is a direct plug-and-play replacement. Simply disconnect the battery negative terminal first, swap out the old module, route the wiring harness along the instrument panel gap, and attach the adhesive sensor probe near the rearview mirror base. No cutting or splicing is required.
Q: What are the three lighting modes on this sensor module?
A: The module offers Tunnel Mode (1-second reaction time), Normal Mode (3-second reaction time), and Delay Mode (5-second reaction time), allowing you to customize how quickly your headlights respond to changing light conditions.
Q: Will this module drain my car battery when the vehicle is off?
A: No. The module includes built-in battery protection — headlights automatically turn off before the car starts and turn on 3 seconds after the engine starts, helping to preserve your vehicle battery.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.