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How Does it Work /
Fuse
How a Car Fuse Works
The primary purpose of an electrical
fuse is to help protect a
circuit from damage in the event of a short. A fuse is designed to break stopping
the voltage flow in the event of a power overload or short circuit. Each vehicle
has several fuses
that are necessary to safe guard electrical circuits.
Electrical Fuse
Checking Fuses
(always wear protective safety goggles and gloves before work begins)
Electrical fuses protect vulnerable electrical circuits from shorts and burnt
wiring. There is basically only one way a fuse can fail and that is, for at least
a second there was a short circuit to ground that caused the fuse to blow. Most
vehicles fuse panels are located under the hood or under the dash and is labeled
with specific amperage ratings and the circuit the fuse protects. Always replace
failed fuses with the proper amp fuse, not doing so can result in electrical system
damage.
Identify fuses, control relays, micro relays and main fusible links:
This is a main electrical junction box, most electrical components are supplied
and protected though this box. If an electrical component short circuits it will
blow a fuse in this box in most cases. The control relay and micro control relay
are used as a high amperage switch for devices that require high amounts of amperage
for an extended amount of time. The fuse or fusible link supply voltage to sub electrical
systems.
Checking Fuses and Main Fusible Links:
There are two ways to check fuses the first is the good old fashion way of removing
each fuse and visually inspecting each fuse. It's time consuming but effective.
And the easy way, but you need a "test light" before you can begin. Turn the key
to the "on" position (do not start), ground your test light lead to a good ground
source, like a metal brace under the dash, seat mount bolt or under hood brace.
Then lightly touch the service port at the top of the fuse on both sides. If the
test light illuminates on both sides of the fuse, the fuse is ok and working properly.
If the fuse lights the test light on one side it is blown and needs to be replaced.
If a blown fuse is discovered replace the blown it with a new unit. Always replace
fuses with the manufactures recommended amperage. If the new fuse blows immediately
you have a shorted circuit somewhere in that wiring system. Consult a
repair manual to locate the wiring schematic for your car. Then trouble shoot
to system by inspecting the wiring harness and accessories, repair as needed and
recheck system.
Common Problems and Solutions
- Wrong amperage fuse is installed causing wiring damage
- Fuses can cause intermitted short circuit by becoming loose or corroded
in the fuse holder. Make sure fuse is held securely and is free of dirt and
corrosion
The most common cause of a short tends to be when a piece of wire has a small
exposed area that is bare. This piece of bare wire can often rub against metal and
create issues for the electrical system because of the sudden surge in electrical
current. While there can be numerous causes for a blown fuse, the majority of the
causes of a blown fuse tend to be quite simple to repair. Once the failed wire is
located the solution usually takes only a few moments to correct. Usually something
as simple as repairing a bare wire.
Maintenance
There is very little maintenance that needs to be performed on the fuse system.
A visual inspection of the fuses in your car occasionally and replace any necessary.
Most fuses are inexpensive costing only a couple of dollars for a pack of five.
Looking under the hood on occasions for bare wires can also help. Anything that
looks bare, or appears to be losing its insulated coating should be thoroughly taped
with electrical tape to help ensure that the wire does not start causing problems
with your fuse system or other electrical components. Avoiding proper maintenance
on your car, no matter how simple can result in extremely costly repairs.
How Does it Work
/ Fuse
Check Manufacturer Specific Fuse
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