Fuses are used to prevent damage to the electrical circuit. They sacrifice themselves by “blowing” if too
much power tries to surge into the electrical components.
BURNED-OUT BULBS
Exterior bulbs usually burn out first because they are used most frequently.
DEAD BATTERY
Automotive batteries have a finite lifespan and need to be changed regularly. You may have heard that
cold weather will shorten the life of a battery, but it’s actually hot temperatures that cause damage. Heat
will expand the fluids in the battery, shortening its life. Overcharging the battery can also cause damage.
Damage to batteries usually occurs in the summer, and the failure happens in the winter.
When changing a battery, make sure your new battery is the proper size and that the rating in cranking
amps is at least as high as the original battery.
CHARGING SYSTEM FAILURE
The charging system runs off the engine and creates the power to recharge the battery and run the electrical
components while the car is operating. The battery relies on the charging system to keep it topped off
with power, and when it fails, the battery is the only power source keeping the engine running and the
lights on. The charging system can fail by not charging enough (or at all), or by overcharging and
damaging the battery. Keeping the battery connections clean is essential for the charging system to work
properly.
Also, if you customize your car with power-hungry electrical components, such as big stereos and offroad
lights, make sure your charging system is capable of covering the added energy needs.
STARTING SYSTEM FAILURE
The starting system uses more power than anything else on your car. The starter can wear out due to heat
from the exhaust, corrosion, wear on the teeth that turn the motor, or the battery can simply run out of
power.
Because the starting system uses so much power, it is important that the wiring is capable of carrying the
needed power, and that the contacts are kept clean. Inspect the wiring frequently for damage and
corrosion, and to ensure that they make a good connection.
GROUNDING ISSUES
An electrical circuit must travel back to where it started (the battery) to operate properly. To do this, your
car uses the metal parts of the chassis as a grounding source for the electrical circuits, and the ground wire
is connected to the battery.
Grounding issues are frequently the problem when you have a faulty circuit. The bolts holding the
ground wires can loosen, and the wires can be damaged or become corroded.
Some ground wires are buried deep in the car and should be left to the pros to find and repair. If you
notice the ground points while working on your car, make sure that the contact with the metal frame is
good and not corroded. Try to keep them clean.
