Why do fuses blow in cars

It protects the devices by cutting the connection thereby preventing a power surge or overload in the device or system. Then study the circuit assigned to each fuse. It is shown in the diagram.

The lid of the fuse box can be removed by hand or by a flathead screwdriver in the latest models of vehicles. Some fuses can be removed by hand while others can be removed using a pair of tweezers or needle-nosed pliers.

Inspect the fuses for wire connections, burn marks, etc. They are easily available at any car parts or hardware store and cost a few cents. Usually, the fuse blows due to incorrect amperage rating. Check what systems and devices are powered by that circuit. They may be pulling too much power from it causing the fuse to blow. This is called the load.

The larger the number of devices on the circuit the heavier the load on it. The fuse also blows due to a low resistance connection between conductors in a circuit.

There are 3 other reasons why fuses blow and each has a tell-tale sign. The first reason may be that the device has failed. For example — the motor of the wiper or the power lock solenoid has melted. This causes the device to draw too much power to keep functioning. The overload in the system causes the fuse to blow. The second reason may be friction against the wire harness which may cause the insulation to fray.

The exposed wire may cause a short circuit if it touches a ground surface. It may come in contact due to gusts of breeze or jostling while the car moves.

Depending on the car, the fuse panel location and components would vary. You would find one of the boxes in the engine compartment while another one under the steering wheel. You are required to use the owner's manual to find the exact location.

Take off the panel's cover. To access the fuses, you have to open the panel's cover. There you would see different types of fuses with a range of colors and numbers too. The diagram on the top of panel would give you the function of each exact fuse.

Figure out the blown fuse. It is often easy to locate the blown fuse, as you need to look at one with a black interior or broken metal filament.

This shows that the fuse melted its metal filament to break the circuit. If the fuse box is in a dark place, use a flashlight to locate the blown fuse. Remove the broken fuse and replace it. Using needle-nose pliers or some small tweezers, remove the broken fuse and in its place replace with a new fuse. Car Review. Car Comparison. Industry knowledge. Why Fuse Keeps Blowing in Car?

By Tsukasa Azuma. Last updated Jan 22, What Causes Fuse Keeps Blowing in Car Every vehicle equipped with the fuse box has it somewhere hidden within the glove box, below the steering column, or near the feet area. Incorrect Fuse Size or Damaged Amplifier When the wires of the amplifier are connected in the wrong fuse or being tossed in the vehicle, it damages the internal structure of the component and causes the fuse to blow up as soon the power is supplied.

Resistance The damaged power wire or the one lesser in diameter causes the abundance of resistance. Touching a power supply wire off the body is the same as touching it off the negative side of the battery post — creates a shortcut to battery negative. Chafing can happen simply as the vehicle ages, vibration causes wiring looms to sag and lay up against chassis and engine components.

Problems can be introduced by not securing looms after repairs, not uncommon for looms to lay against hot exhaust components burning through the insulator and causing you to know what. Electrical damage is likely to kill a car long before rust gets it. If a car leaks water unnoticed or is not repaired, strange things begin to happen.

Electrical components start to do their own thing. Water in the electrics allows voltage to take a shortcut and flow from the positive circuit through the water to the ground and of course, that causes a short and the fuse blows. Could be a light, motor, heater element, etc. The load has a wiring circuit too, which is also prone to failure. Many electrical components include a motor and motor failure is common, they generally suffer from one of three failures:.

To help eliminate component failure as a possible cause of the short. Try unplugging it and replace the circuit fuse. If the fuse blows immediately or activating the components switch causes it to blow, you know the component is good and you are instead chasing a wiring short problem.