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9.1 YOUR CAR'S WARNING LIGHTS - THE FIRST LINE OF DEFENSE; AUTOMOBILE REPAIR AND
MAINTENANCE
By
Don Patten
Don
Patten is a leading expert in automotive education. His text book Automotive Service
Basics published by Prentice Hall is used in automotive instruction courses world
wide.
Most
vehicle operators skip over testing the most important safety and protection feature on
the vehicle. This check is very simple to make and should always be made each time the
vehicle is started. What we are referring to is the warning light test, a test of the
light system which lets us know when something is not right and immediate action is
required to prevent failure or serious damage.
Warning
lights are used on all vehicles. A light is used on many vehicles when the charging system
fails to put out the right voltage for a correct battery charge. Some vehicles have a
light to tell if the engine oil pressure is at a safe level to prevent engine damage.
There are lights used to tell if the fuel is low, if your seat belt is fastened, when
emission control parts fail, and when the engine temperature gets too high to safely run
the engine.
Always
refer to your vehicle operation manual for a complete listing of all the lights on the
make and model you own. Some vehicles use gauges and others use lights. In the case of
fuel there may be a gauge to tell the level and a light to warn the driver if the fuel is
getting too low. There are systems that have a light to warn of brake failure and a light
to tell when brake fluid is getting low. The list is getting longer.
Once
you know what warnings lights are installed in your vehicle there is another problem. How
are these systems tested so they can be ready in case of a problem? Get into your vehicle
and turn the key to the "ON" position. Some but not all of the warning lights should
light. This is where you should do your own research.
Find
out which lights can be tested in this key position on your specific vehicle. If any light
should be lit but is off, either the bulb or the wiring is defective and will require
further testing and repair. That light should be ready to warn you in case of a system
failure. Next, turn the key to the "START" position (never hold the key in this position).
While the engine is being cranked and before releasing the key, certain lights should come
"ON". Again it will take some research to identify which systems are checked in this key
position for your particular vehicle.
One
example of a light that should always be checked in the "ON" key position is the low oil
pressure light. When the engine is not running there will be no oil pressure so a low oil
pressure warning should be lit at this time. An example of a light that should come on in
the "START" position is the hot engine light. The engine will be cold when it is not
running and may never get hot enough for a overheat light reaction. You can not test this
light in the "ON" key position as it would stay lit all the time. The only way to check
this light is in the "START" position where it should light and come off when the key is
released. Door ajar, and trunk lid open lights can be checked by opening each item with
the key in the "ON" position.
Some
of these items are not critical, but there could be a time when you may depend on the
system to give a warning. It can not if a bulb or the wiring is defective. Bulbs, switches,
wiring, fuses, and sockets can always fail. It is up to the vehicle owner to make sure
these items are tested and serviced when needed. One inexpensive part such as a bulb could
cost you an expensive four thousand dollar engine replacement.
I
need to add one more thing. Always know how to react if a warning light flashes on.
Sometimes the vehicle can be driven to the nearest repair facility and other times the
engine has to be shut off immediately. Learn some basic inspection techniques. Everyone
should know how to check the oil and radiator level. You should know how to inspect the
alternator belt and check the brake fluid. We could add to this list but you get the
point. I have always said that the major problem with the automobile is the loose nut
behind the steering wheel. I don't think this will ever change. Each engine start can be
an informed test. Good luck!
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