1. Introduction
This instruction manual provides essential information for the safe and effective installation, operation, and maintenance of the SYLVANIA 39431 64111 12V5W Miniature Automotive Light Bulb. Please read this manual thoroughly before installation and retain it for future reference.
2. Safety Information
- Always disconnect power to the fixture or vehicle circuit before attempting to install or replace the bulb.
- Allow the bulb to cool completely before handling to prevent burns.
- Do not exceed the specified voltage (12V) or wattage (5W) for this bulb.
- Handle the bulb by its base to avoid touching the glass, as oils from skin can reduce bulb life.
- Dispose of old bulbs according to local regulations.
3. Product Overview
The SYLVANIA 39431 64111 is a 5-watt, 12-volt T2.75 miniature halogen incandescent light bulb featuring a BA9S bayonet base. It is designed for various automotive and general-purpose applications requiring a compact, low-wattage light source.

Figure 1: SYLVANIA 39431 64111 Miniature Automotive Light Bulb. This image shows the clear glass bulb with its internal filament structure and the metallic BA9S bayonet base, which has two small pins for secure fitting and a contact point at the bottom.
Key Features:
- Average Lifetime: 240 hours
- Lumens (light output): 80.42
- Base Type: BA9S Miniature Bayonet Base
- Voltage: 12V
- Wattage: 5W
- Light Type: Halogen Incandescent
4. Setup and Installation
- Power Disconnection: Ensure the power supply to the light fixture or vehicle circuit is completely turned off before beginning installation. This prevents electrical shock.
- Access the Bulb: Carefully remove any covers, lenses, or housing components to gain access to the existing bulb. Refer to your vehicle's service manual or fixture instructions for specific access procedures.
- Remove Old Bulb: Gently push the old bulb into its socket and twist counter-clockwise to release it from the BA9S bayonet base. Pull the bulb straight out.
- Install New Bulb: Hold the new SYLVANIA 39431 64111 bulb by its metallic base. Align the two pins on the bulb's base with the slots in the socket. Push the bulb into the socket and twist clockwise until it locks securely into place. Avoid touching the glass portion of the bulb.
- Reassemble: Replace any covers, lenses, or housing components that were removed.
- Test: Restore power and test the new bulb to ensure proper function.
5. Operating Instructions
Once properly installed, the SYLVANIA 39431 64111 bulb will illuminate when power is supplied to its circuit. This bulb is designed for on/off operation and does not support dimming unless the fixture or vehicle system explicitly supports incandescent dimming for this bulb type.
6. Maintenance
- Cleaning: If the glass portion of the bulb becomes dirty, ensure power is off and the bulb is cool. Gently wipe with a clean, dry, lint-free cloth. Avoid abrasive cleaners.
- Inspection: Periodically inspect the bulb and its socket for any signs of wear, corrosion, or damage. Replace the bulb if the filament is broken or if the glass is cracked.
7. Troubleshooting
Bulb Does Not Light:
- Check Power: Ensure the power supply to the circuit is active.
- Verify Installation: Confirm the bulb is securely seated in its socket and twisted clockwise to lock.
- Inspect Filament: Visually check the bulb's filament for breakage. If broken, the bulb needs replacement.
- Check Fuse/Circuit: For automotive applications, check the relevant fuse or circuit breaker.
- Test Socket: If possible, test the socket with a known working bulb to rule out a faulty socket or wiring issue.
8. Specifications
| Specification | Value |
|---|---|
| Brand | SYLVANIA |
| Model Number | 64111 (Part Number: 39431) |
| Light Type | Incandescent, Halogen |
| Wattage | 5 Watts |
| Voltage | 12 Volts |
| Bulb Shape Size | T2.75 (T) |
| Bulb Base | BA9S Miniature Bayonet |
| Brightness | 80.42 Lumens |
| Average Life | 240 Hours |
| Light Color | White |
| Material | Copper (base) |
| Indoor/Outdoor Usage | Outdoor (as per specification, but generally applicable to enclosed automotive fixtures) |
| Item Weight | 0.9 Pounds (approx. 14.4 ounces) |
9. Warranty and Support
For information regarding warranty coverage or technical support for your SYLVANIA 39431 64111 Miniature Automotive Light Bulb, please refer to the official SYLVANIA website or contact their customer service department. Keep your purchase receipt as proof of purchase.
SYLVANIA Official Website: www.sylvania-automotive.com







