If you don't have the owner's manual, you can try these steps:
1. Check the underhood fuse box: This is usually a larger fuse box located under the hood, often near the battery. The cover should have a diagram.
2. Check the interior fuse box: Many vehicles also have a smaller fuse box inside the cabin, often located in the glove compartment, under the dash, or in the center console. Again, the cover will likely have a diagram.
3. Look for "Power Outlet," "Accessory," or "Cigarette Lighter": The fuse may be labeled with one of these terms, not necessarily "Cigarette Lighter."
4. Use a test light or multimeter: If you can't find it visually, you can use a test light or multimeter to check the fuses individually. This requires some electrical knowledge and caution.
Without the owner's manual, pinpointing the exact fuse location is difficult. The best approach is to carefully examine both fuse boxes with their diagrams.