How to Find a Faulty Fuse in a Car

Faulty fuses will cause your dash gauges and engine sensors to operate erratically and overload wiring which results in short and open circuits. It is important to locate the faulty fuse as soon as possible to avoid costly repairs later on. Read on to learn how to find a faulty fuse in a car.

Instructions

1

Locate the fuse box on your vehicle. The fuse box is usually located under the dash and near the left side of the driver's seat.

2

Once you locate the fuse box, gently remove the plastic cover taking care not to damage it. Set the cover aside and do a visual inspection of the open fuse box and the wiring harness behind it. Look for melted wires in the wire harness and burned fuses in the fuse box. Use your inspection mirror to check wires and fuses that cannot be seen by a visual inspection.

3

If you find melted wires, remove the tape from the wire harness and separate the melted wires from the rest of the harness. Cut out the melted wire or wires, and use your wire strippers to remove the insulation on both ends of the cut wire. Use the appropriate size wire connector and use your wire crimpers to reconnect the wire ends.

4

Once you have replaced any burned wires, hook up your test light by attaching the ground lead to a solid metal grounding source. Test each fuse for continuity by using the probe end of your test light. Check the positive and negative sides of the fuse your are testing. The test light should light up if the fuse is operational.

5

Once your locate all the faulty fuses, use your needle nose pliers to gently pull the fuse from the fuse box. Do a visual inspection of the faulty fuse. If you see the metal connectors inside the fuse are separated or the fuse is melted, your diagnosis is confirmed and you can proceed to the replacement of the fuse. Make sure to replace the fuse with a new one that is the same amp rating as the faulty fuse. Use your needle nose pliers to install the new fuse. Use your test light to ensure the new fuse is functioning.

6

Replace the plastic fuse box cover and check your dash gauges and sensors to ensure they are working properly.