Bmw E39 Cigarette Lighter Fuse

The cigarette lighter, also known as the auxiliary power outlet, in a BMW E39 provides a convenient source of 12V power for various electronic devices. A blown fuse is a common issue, rendering the outlet useless. Understanding the fuse location, replacement procedure, and potential causes of failure is essential for any E39 owner to maintain functionality and prevent electrical problems.

Benefits & Purpose of the E39 Cigarette Lighter

• Powering Devices: Provides 12V DC power for charging phones, GPS units, radar detectors, and other accessories.
• Convenience: Offers a readily available power source for drivers and passengers.
• Essential Functionality: Needed for some diagnostic tools and essential accessories.

Understanding the E39 Cigarette Lighter Fuse and Circuit

The cigarette lighter circuit in a BMW E39 is protected by a fuse. Knowing the fuse location and amperage rating is vital for replacement. Typically, the cigarette lighter fuse also protects other components, so its failure can affect multiple systems. For more related activities, check out our Star Delta Starter Timer Connection.

The fuse location varies slightly depending on the model year, but is generally found within the glove box or in the trunk’s fuse box. Consult your owner’s manual for the exact location of the BMW E39 cigarette lighter fuse. The fuse amperage is typically 20 amps.

Here’s a general process to locate the fuse:

1. Locate the Fuse Box: Open the glove box or trunk area to find the fuse box.
2. Refer to the Fuse Diagram: Consult the diagram inside the fuse box cover to identify the cigarette lighter fuse. Look for symbols or descriptions related to auxiliary power or cigarette lighter.
3. Visually Inspect: Once located, visually inspect the fuse for a broken filament.

Replacing the BMW E39 Cigarette Lighter Fuse

Replacing a blown fuse is a straightforward process. Follow these steps to ensure a safe and effective replacement:

1. Turn Off the Ignition: Ensure the car is switched off to prevent short circuits.
2. Locate the Fuse: Find the correct fuse using the fuse box diagram.
3. Remove the Blown Fuse: Use a fuse puller (usually located in the fuse box) or a small pair of pliers to carefully remove the blown fuse.
4. Inspect the Fuse: Confirm the fuse is indeed blown by visually inspecting the filament. A broken filament indicates a blown fuse.
5. Install a New Fuse: Insert a new fuse with the correct amperage rating into the fuse slot. Important: Using a fuse with a higher amperage rating can damage the electrical system.
6. Test the Cigarette Lighter: Turn on the ignition and test the cigarette lighter to ensure it is working.
7. Check Other Components: Because it may protect other components, verify other systems are working.

1. Troubleshooting & Common Issues

If the cigarette lighter fuse blows repeatedly, it indicates an underlying issue in the circuit. Common causes include:

• Overload: Plugging in devices that draw more power than the circuit can handle.
• Short Circuit: Damaged wiring or faulty accessories causing a short circuit.
• Faulty Cigarette Lighter Socket: A damaged socket can cause intermittent shorts.

2. Tips & Best Practices

• Use Quality Accessories: Avoid using cheap or poorly made accessories that can cause electrical problems.
• Do Not Overload the Circuit: Be mindful of the power requirements of the devices you plug in.
• Regular Inspection: Periodically inspect the cigarette lighter socket for damage or debris.
• Consult a Professional: If you are unsure about any electrical repairs, consult a qualified mechanic.

FAQs About the BMW E39 Cigarette Lighter Fuse

Q: What amperage fuse does the BMW E39 cigarette lighter use?

A: Typically, the BMW E39 cigarette lighter fuse is rated at 20 amps. Always consult your owner’s manual for the specific amperage rating for your model year.

Q: Where is the fuse box located in a BMW E39?

A: The fuse box is usually located in the glove box or in the trunk, depending on the model year.

Q: What happens if I use a fuse with a higher amperage rating?

A: Using a fuse with a higher amperage rating can damage the electrical system and potentially cause a fire. Always use the correct amperage rating.

Q: My cigarette lighter fuse keeps blowing. What should I do?

A: A frequently blowing fuse indicates a problem in the circuit. Check for overloaded circuits, shorted wires, or a faulty lighter socket. If you cant identify the problem, consult a qualified mechanic.

Q: Can a blown cigarette lighter fuse affect other electrical components?

A: Yes, the cigarette lighter fuse circuit may also protect other accessories or components depending on the wiring in your specific model year, so other functionalities may be affected.

Conclusion

Maintaining the functionality of the cigarette lighter in your BMW E39 is essential for powering accessories and diagnostic equipment. By understanding the fuse location, replacement procedure, and potential causes of failure, owners can address common issues quickly and effectively. Regular maintenance and cautious usage prevent fuse failure, ensuring the E39’s electrical system operates reliably. Always consult the owner’s manual and follow safety precautions when working on electrical components.