Car Care - Your Car's Electrical
by: Kevin Schappell
When the automotive industry was in its infancy, it used electricity
only to ignite the fuel inside the engine. By the late 1920's, the
electric starter replaced the hand crank, electric headlights made
acetylene lamps obsolete and the braying of the electric horn drowned
out the squeak of the hand-squeezed air horn. Today, an automobile
requires an elaborate electrical system of circuits just to produce,
store, and distribute all the electricity it requires simply for
The first major component in the electrical system is the battery.
The battery is used to store power for starting, and for running
auxiliary devices such as clocks, radios and alarms when the engine
is off. The next major component is the starter motor, which is
used to start the engine. The third component is a charging device
powered by the engine, known as the alternator. It powers the electrical
system when the car is running, and restores the charge within the
battery. With these basic components, the car maintains its supply
of electricity. A device called the voltage regulator keeps the
power level stabilized, and the fuse box keeps minor problems from
becoming major ones.
Many different auxiliary electrical devices are used in modern cars,
such as: radios, cellular phones, rear window defrosters and electric
door locks, as well as a vast array of motors powering everything
from the moon roof on down.
The above information is directly from the Auto Insight program,
which you can buy online from AutoEducation.com.
* The battery is usually the first part of the system to wear out.
Most batteries last between 3 and 7 years depending on brand and
design. Batteries can be fine on minute, and dead the next. More
on this later.
* Blown fuse: Is one part of the electrical system not working like
the interior lights or dash lights? The first thing to check is
the fuses. Look for the fuse panel under the dash, in the glove
box, or even in the engine compartment in some cars. Most fuse boxes
will be labeled by circuit. Modern cars use a blade type fuse which
is rectangular in shape and transparent. Look for the wire, which
runs through the fuse, and see if it is burned through. Any discoloring
of the fuse is a good sign the fuse has blown. If you have doubts,
replace with a new fuse and test the system, which is not working.
* Alternator: Does your car start ok, but your headlights dim when
idling. It could be a bad alternator. When the alternator cannot
produce enough electricity to keep the electrical systems running
and the battery will have to be used to take up the slack. This
will eventually wear down the battery and not allow your car to
I don't think there is a tougher system to troubleshoot on your
car than the charging/starting system. This is due to the fact that
there are many things that can go wrong and it's tough to test some
components without special equipment. Let's go over some possible
situations and their possible causes.
* Car won't start, all I hear is a click but the engine does not
o First check all battery cables for corrosion as this will keep
power from flowing freely to the starting system. If they are dirty,
clean with a wire brush and reattach. Apply a light coat of grease
to the top of the terminals to prevent further corrosion.
o Battery could not have enough power stored in it to spin the engine.
This can be caused by a bad cell in the battery or from a bad alternator
not charging the battery when the engine is running. If you can
get the car to a mechanic, have him or her test the battery and
charging system with a special tester. This tester places a load
on the battery and can tell the condition. They can also check to
see if the alternator is working to it's full potential.
o Starter or solenoid could be bad. If you can not jump start the
car and all of the battery cables are ok then suspect the starter.
* Car won't start, I hear nothing.
o Check battery cables as above.
o Have the battery tested. There could be a bad cell causing a short.
You can try jump-starting but often the car will not stay running.
* Car won't start, all I hear is a horrible grinding noise.
o Grinding noises point to the starter not properly meshing with
the flywheel. This can be caused by a bad solenoid or a bad spot
on the flywheel.
o I have also seen starters loosen up so they no longer contact
the flywheel at the proper distance. While not common, it is something
to keep in mind.
* Car starts but my headlights are dim at low engine speeds.
o Look to the alternator for problems. Take the car to your mechanic
to have the alternator checked for proper operation.
o Check for loose wires going to the alternator. Also check for
corrosion, as this will inhibit the alternator from charging properly.
o Check the tension on the alternator belt. If it is too loose,
the belt may slip and not drive the alternator properly.
As you can see there are plenty of things to go wrong with the charging
system and it is always best to take the car to your mechanic and
have it tested before you go replacing parts blindly.
Preventing problems with your electrical system:
* Replace your battery every 4 years as a safety measure. It will
save allot of headaches down the road.
* If your battery is not a sealed unit, check fluid levels in each
cell. Only fill with distilled water and be careful around the acid,
which is in the battery.
* Check your alternator belt frequently for cracks and tension.
Replace per your cars manufacturers recommendations.
* Clean your battery connections at least once a year. Parts stores
sell a handy terminal cleaner which is basically a round wire brush,
which works wonders. Once you reattach the terminals, coat with
a layer of heavy grease or special purpose grease sold at parts
stores. This layer will block the air from reacting with the connectors
and creating corrosion.
How to jump start your car:
Jump-starting your car does not have to be a hard task. First lay
out the cables on the ground between the two cars. Make sure that
the cable is not tangled and none of the end clamps are touching
each other. The car with the good battery should be running.
Step 1: Take the positive (red) clamp closest to the car with the
good battery and hook it to the positive terminal of that car. The
positive terminal will have a + sign on it and usually a red wire
running to it.
Step 2: Repeat this step on the car with the bad battery, hooking
up the positive clamp to the positive terminal on the battery. Make
sure the clamps are contacting well and can not fall off.
Step 3: Take the negative cable (black) closest to the car with
the good battery and hook it to the negative terminal of the battery.
The negative terminal will have a - sign and usually a black wire
running to it.
Step 4: This is the last step and the most important. Take the negative
clamp closest to the car with the bad battery and attach it to a
bare metal part of the engine. DO NOT hook it to the batteries negative
terminal as there maybe hydrogen gas present from the battery and
a spark from the connection could cause an explosion.
That's it...... turn the key on the dead car and the car should
start. If it does not, try revving the engine on the good car to
boost the charge coming from the alternator. If this does not work,
try wiggling the cables to assure you have a good connection. GOOD
sets of jumper cables are a necessity. I have had cheaper sets not
jump-start a dead car. I actually had to double up two cheap sets
to get enough current to start my car. The cheaper sets will have
thinner cables, which cannot carry enough amperage to start some
stalled cars. I would suggest buying a cable, which has 4,6 or 8-gauge
About The Author
Kevin Schappell maintains http://www.carbuyersclub.com where he
gives advice on buying, selling, insurance, and financing. A mechanical
engineer and car guy, Kevin has decided to spend his online time
helping others learn about automobiles. To learn more about how
your car works, Kevin has created http://www.mycarwizard.com.