This guide demonstrates how to locate and test the various car electrical fuses that protect particular electrical system accessories. When testing a fuse, there are two aspects to consider. First, the integrity of the fuse is subject to failure. The second is to confirm electrical power is present at the fuse. The second is to test for electrical power at the fuse, if the sub-system that powers the circuit is not working i.e. a bad power relay, maxi or fusible link the fuse will not have power and the accessory will not work.
When powering an electrical circuit a designed the amperage to run the accessory is calculated by the engineer. When the amperage pulled through the circuit becomes too excessive the fuse will overheat and blow protecting the circuit or accessory from fire. This condition can occur when a particular accessory wears out or when electrical power connects to the ground of the car for example the body, frame, drive train or interior metal parts. It is important to know that a fuse can fatigue and fail as well.
Car Fuse Test
Most cars are designed with multiple fuse panels which are usually located under the hood, in the interior of the car or in the trunk. These panels are commonly known as the PDC (power distribution center) or fuse and relay panel which can be identified by having a black plastic cover over the top or side of the panel. Each car is different, an owners manual will indicate the location and fuse designation. If you don't know where a particular fuse is located please ask one of our experts and they will help find it for you.
A fuse replacement is one of the most reasonable cost repairs in the industry. Almost anyone can test and change a fuse for the simple cost of the fuse which is about $2.00 US. This can vary due to fuse size and design, but most are easy to replace.
If the fuse blows when replaced the protected circuit is shorted to ground via either the wire itself or the accessory has failed internally, in either case a repair is necessary to resume normal fuse operation. If no power is detected at the fuse or panel (either side of the all fuses) use a wiring schematic to trace the power source, usually a main power relay, maxi-fuse or fusible link has failed.
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