A car cigarette lighter typically uses a 15-amp blade fuse, with 10-amp or 20-amp ratings also possible depending on the vehicle. It is located in the vehicle's interior fuse panel, commonly labeled as CIG, LTR, PWR OUTLET, or ACC. Using a fuse with a different amperage can lead to electrical damage or fire hazard.
Identifying the Correct Fuse
The cigarette lighter fuse is part of the vehicle's low-voltage accessory circuit. You will find it in the interior fuse box, usually under the dashboard, in the glove compartment, or on the side panel of the driver's footwell. The fuse box cover or your owner's manual contains a diagram that identifies each fuse by its function. Look for labels such as CIG (cigarette lighter), LTR (lighter), ACC (accessory), or a power outlet symbol. Physically, it is a standard blade-type fuse (ATO or mini-ATO). Its color indicates amperage; a blue fuse is typically 15 amps, a red is 10 amps, and a yellow is 20 amps.
Standard Amperage: 15A is the Common Default
While 10-amp, 15-amp, and 20-amp fuses are used, 15 amps is the standard for most modern vehicles, especially North American and Japanese models. This rating balances sufficient power for common devices (like phone chargers or compact tire inflators) with protective safety margins. Some European vehicles may use a 20-amp fuse for higher-power outlets. It is critical to replace a blown fuse with one of the exact same amperage. Using a higher-rated fuse (like a 20A in a 15A slot) removes the protective function and risks overheating the wiring.
Step-by-Step Replacement Process
- Locate & Access: Find the interior fuse panel. Pull off the plastic cover.
- Identify: Use the diagram on the cover or in the manual to find the specific fuse for the cigarette lighter/power outlet.
- Remove: Use the plastic fuse puller tool (found in many fuse boxes) or needle-nose pliers to gently pull the fuse straight out.
- Inspect: Hold the fuse up to the light. A blown fuse will have a visibly broken or melted metal strip inside the plastic housing. A good fuse's strip is intact.
- Replace: Insert a new fuse of the identical amperage rating into the vacant slot. Press firmly until seated.
- Test: Plug in a simple device (like a phone charger) to verify the outlet is now functional.
Why Do These Fuses Blow? Common Causes
The primary cause is overloading the circuit. The cigarette lighter socket is designed for a specific power draw (e.g., 180 watts for a 12V/15A circuit). Plugging in a device that exceeds this, such as a high-wattage inverter, a faulty air compressor, or multiple high-draw accessories via a splitter, will blow the fuse. Short circuits are another major cause. This occurs when a metal object like a coin, paperclip, or the exposed terminals of a poorly designed plug bridge the positive center contact and the grounded outer sleeve of the socket, creating a direct path to ground. Less commonly, an internal fault in a connected device can cause a surge.
Troubleshooting If the New Fuse Blows Immediately
If the new fuse blows as soon as you insert it or plug in a device, do not continue replacing fuses. This indicates a persistent short circuit or serious fault.
- Inspect the Socket: With the fuse removed, use a flashlight to check for any foreign metal debris lodged inside. Carefully remove any debris with non-conductive tweezers.
- Check the Accessory Plug: The problem may be in the accessory itself. Some cigarette lighter plugs have a small, user-replaceable glass fuse inside their casing. Unscrew the metal tip of the plug to access and check this secondary fuse.
- Professional Diagnosis: If the socket is clear and your accessories work in other vehicles, the issue may be a damaged socket or wiring harness, requiring professional automotive electrical repair.
