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Autodoc£7.35Visit shop OSRAM Light Bulbs MERCEDES-BENZ,VOLVO,MAN 64138 Bulb, indicator
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eBay£12.90Visit shop 64138 Daytime Running Light Bulb ORIGINAL 24V 21W H21W Bay9s Lamp Lighting Osram
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The Osram Original Line H21W Signallampe is a high-quality, reliable lighting solution designed primarily for truck and heavy-vehicle auxiliary lighting, such as front or rear turn signals. It is an ideal choice for fleet managers or drivers looking for Original Equipment Manufacturer (OEM) standards, providing a robust 600 lumens of light output and a stable 24V design. One caveat to keep in mind is that this specific lamp is designed for 24V electrical systems, making it unsuitable for standard 12V passenger vehicle light housings.
| Model Part Number | 4008321094988 |
|---|---|
| Brand | Osram |
No, these bulbs are designed for 24V electrical systems. Using them in a 12V vehicle will result in very dim light or no operation.
The BAY9s is a specific pin configuration for automotive bulbs featuring two offset pins on the side of the metal base for a secure, keyed fit.
This product comes in a pack of 10 individual lamps.
No, these are signal lamps (H21W) and are intended for turn signals, not as primary driving or headlight illumination.
It is recommended to use gloves or a clean cloth, as natural oils from your skin can cause the glass to overheat and lead to premature failure.
Verify that the BAY9s base is fully seated in the socket and check the vehicle fuse panel for blown turn signal fuses.
Ensure the bulb wattage matches your vehicle's requirement; a discrepancy can trigger the vehicle's bulb-out warning system.
Before installing these bulbs, ensure the vehicle's ignition and lighting systems are completely powered off. Access the light housing assembly—usually accessible from behind the lamp cluster on a truck chassis—and rotate the old bulb out of the BAY9s socket. When handling the new Osram H21W, avoid touching the glass with bare hands, as skin oils can cause hot spots and reduce bulb lifespan. Check that your vehicle specifically calls for an H21W category bulb, as improper socket matching will result in a poor electrical connection or mechanical failure. These bulbs do not require specialized tools for installation.
