How to Guides

How To Replace A Fuse

Zaki Moulvi posted this on Jun 4, 2014

Many of your vehicles problems can be traced back to a blown fuse.  Before running to the mechanic for every minor problem you should try to locate and replace it.  This could potentially save you a ton of cash on unnecessary repair shop costs.  Changing a blown fuse is really a simple job that even the most naïve grease monkey should be able to do.

The Job of the Fuse

Just like the ones in your fuse box at home, automotive fuses are designed to protect the electrical system.  For your car, a fuse is made up of two terminals and a fuse element inside of a plastic casing.  It is a bridge within the circuit of whatever vehicular system it is a part of.  If for any reason the system begins to draw more power than it can handle, the fuse element will heat up first, melt and interrupt the circuit.  This protects the part it is serving and alerts you to a problem.

What does it mean when a fuse blows?

Fuses can blow for a variety of reasons.  For example, the one controlling your stereo system may blow simply because you overloaded the system by playing it too loud.  It could also be indicative of a wiring problem.  You really don’t know until you change the fuse.  When a fuse blows, the best thing you can do is change it and then observe how the system reacts.  If it blows again quickly than the part it controls has an electrical issue that you need to address.  If not, it may just have been a temporary glitch or the fuse could have been old.

The Fuse Box

There are usually two fuse boxes found inside of the car.  The one inside of the engine will house the fuses for the larger systems, like your air conditioning and engine functions, while the one inside of the cabin contains the fuses for your electrical accessories.  You will most likely find a map on the inside cover of all the fuses and what they control.  If not, consult the owner’s manual.

Replacing the Fuse

  • The hardest challenge with changing a fuse is going to be finding the right one.  Remember, the larger, more complex vehicle systems will have their fuses inside the fuse box located in the engine.  Smaller systems should be inside the one located in the cabin of your car.
  • Once you have located the right fuse box, consult the graph to find the fuse that is associated with the part you are having trouble with.  If there is no such graph the owner’s manual should have one.
  • When you have identified the fuse use the plug puller or a pair of pliers and pull it straight out.  A fuse has blades like the plug on a household appliance which could break off you try and pull it at an angle.
  • Examine the fuse carefully.  Like a light bulb there is a filament inside that runs between the two blades.  On a blown fuse you will see an obvious break in that filament.  If the filament is still intact, your problem is not with the fuse.
  • When replacing the fuse be sure that it is of the amperage of the one you removed.  Double check this on the graph or your owner’s manual as the problem could have been caused by the wrong fuse being used. 
  • After the new fuse has been installed check the corresponding part to make sure that it is now functioning properly.  Some of your more complex automotive systems may have two or more fuses associated with them that may all need to be replaced.

Important Tips:

  • Some vehicles may still employ tubular fuses made of glass.  If that type of fuse is the culprit you need to remove it carefully with a small set of pliers or screwdriver.
  • Don’t change any fuses while the car is running.  While the amperage is generally low, you could still receive an electrical shock.
  • Always ensure that the fuse you are installing is the correct amperage, despite what the one you removed is.  You will generally find complete sets of new fuses sold as a package, giving you a variety of the possible fuses you may possibly need for your vehicle.  They will be color coded to help you identify them easily.
  • If you continuously are changing the same fuse or series of fuses then you have a more complicated electrical problem that needs to be addressed by a qualified mechanic.

As simple as changing a fuse may seem to be, it does need to be correctly in order to ensure that your vehicle continues to run properly.  If you have any doubts or just like to see a pro in action take a few minutes and check out online videos that illustrate exactly how to get the job done.

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