An Idiot's Guide to Car Fuses

Car problems can be really expensive and usually mean you are inconvenienced in some way or other. Some car problems are common and can be easily remedied at home, with blown fuses mostly being something you can manage yourself. For more serious issues you'll need to find a mechanic, but in all cases, the more you know about your car, the less time and money you waste getting issues sorted.

Problems relating to automotive fuses are relatively easy to figure out and fix yourself, so if you've found yourself with a faulty power window or inoperable headlights, take some time to read through our quick guide to fuses before spending an arm and a leg on diagnostics - it may be something you can do yourself.

Fuses are designed to protect the electrical wiring in your car by 'blowing' when there is too much current or a short-circuit in the electrical system. Technically, a fuse protects the electrical system by disconnecting the circuit if there is a dangerous level of current somewhere. And, when a fuse has blown, it's easy to track down and replace, restoring current to the system.

Though they are all designed with the purpose of protecting your car's electrical components, there are various types of car fuses depending on the type of car, where it was built, and its age. To help you identify what electrical fuses your car has, in the event that your car exhibits some electrical mishaps, here are the most common types of fuses used in cars new and old:

• Blade Fuses - Blade fuses are the most common types of fuses used in modern cars. They're identifiable by their plastic housings which have two or three protruding metal prongs. There are various types of Blade fuses: Maxi (heavy-duty), Regular (ATO/ATC), LP Mini (low-profile), Micro2, and Micro3.
• Bosch Fuses - Also known as torpedo, European, continental, or GBC fuses, Bosch fuses were used in old European cars manufactured before 1980. They're identifiable by their conical ends and elongated dimensions (6x25mm) and are color-coded for their current. For example, yellow for 5A, red for 16A, and blue for 25A.
• Glass Tube Fuses - Before the mid-1980s, glass tube fuses were commonly used in most American cars. They vary in length and diameter but all have a metal strip that passes through the center.
• Lucas Fuses - Used predominantly in British-made or British-assembled cars manufactured before the mid-1980s, Lucas fuses can be ceramic or glass. They measure either 1 or 1.25 inches in length and the diameter sizes of the glass car fuses can differ.
• Limiter Fuses - Limiter fuses, or current limiting fuses, come in all shapes and sizes. Inside of each is an element that melts when the electric current passing through it exceeds the specified current limiting range. It then creates a high resistance to the amplitude and duration of the current to protect the electrical circuit and connected components.

Knowing how to tell if a fuse in your car is blown and knowing how to change a fuse can save you plenty of time and money. So use this quick guide to understanding fuses and how they can blow to easily determine if that's the problem.

When an electrical component in your car draws a stronger current than what it was designed to handle, the fuse that that component is linked to may blow as a protective measure. When a fuse blows, it's a sign that there's a short circuit somewhere within your car's inner workings. This can happen due to a basic device malfunction such as a defective switch or faulty wires, but any kind of mechanical mishap with a motor or an electrical component can be the cause.

So if any of your power-operated features, such as the windows, seat-position controls, or side-view mirrors stop responding to input, it could be a sign that one of your car's fuses is blown. This can, however, extend to the powertrain and chassis electronics, driver-assistance technologies, safety systems, and other occupant features, too.

To check the fuse, you will need to locate the fuse box, identify the correct fuse for the system that has stopped working, and check if there is a fuse failure. Let's break it down into a step-by-step process.

Vehicle fuse boxes are typically located beneath the steering wheel column or within the engine bay of modern vehicles, but it really depends on the vehicle and the type of car fuses the box is housing. Whether your car is a heavy-duty truck like a Chevrolet Silverado 3500HD, a lightweight Kia Forte, or a small SUV, you should have relatively easy access to the box.

• Step 1: Locate your car's fuse box - Fuse boxes for cars are usually located beneath the driver's steering wheel column but can also be somewhere beneath the hood. You can check your car's user manual to determine the exact location.
• Step 2: Read the fuse-change tutorial - On the inside of the fuse box, there's usually a diagram that denotes what each fuse in the box is used for and stipulates each fuse's amperage rating. This is also available in the owner's manual. If all else fails, Google is your friend and there are forums and even YouTube channels dedicated to this.
• Step 3: Locate the blown fuse - Locate the fuse you believe is blown and look for either a black burn mark or a broken filament which indicates that the fuse has blown. You can also use a multimeter or test light to identify the dead fuse without having to pull it out.
• Step 4: Remove the blown fuse - Now that you know which fuse is likely the blown one, unplug or unscrew the fuse from the box carefully - you may need pliers for this.
• Step 5: Insert the replacement fuse - If you've followed each step properly, you'll know how to check for the fuse amperage rating. Ensure that the new fuse's amperage is the same as the one you're replacing. In some cases, there may be spare fuses already stored in the terminal box.
• Step 6: Test the replacement fuse - Start up your car so that you can check whether or not replacing the fuse has worked. If the primary problem persists or if the fuse blows out again, then there could be a more serious problem with your car and you'll have to take it to a professional. Here's our handy guide on choosing a good mechanic to help make this process easier.