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.
What goes wrong?
Again, with the key still in the on position start checking for power at all
fuses, ground the test
light and touch the point to the top metal tangs on both sides of the fuse.
A fuse with power on just one side is blown and needs replacement. Note: Some fuses
will not have power on either side due to nonuse of the fuse at the time. When testing
lighting system fuses etc its best to have the system in question turned to the
on position.
Once you have found the bad fuse remove the unit using your fingers or a small
pair of pliers. Sometimes there will be a tool located inside the fuse panel to
help with the removal. This is what a bad fuse looks like compared to a good one.
Replace failed fuses with proper amp rating, not doing so can result in electrical
system damage. Also, fuses can cause intermittent open circuits by becoming loose
or corroded in the fuse holder, make sure fuse is held securely and free from dirt
or corrosion.
Watch the Video!
Please watch this video of the job being done, then continue down the guide to glean additional helpful information.
Good to Know
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.
Questions?
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