The electrical system
of your car has several different voltage and amperage demand systems. The engine
starter circuit is designed
to carry draw volts at high current (amperage). This is why a
battery cable is larger in diameter
compared to other wires in the electrical system. When the
ignition key is activated
the starter will turn the engine over. If it doesn't we have listed below some of
the most popular causes for starter non-operation.
Troubleshooting
Test Electrical System Voltage - The best way to test for electrical
system voltage is to use a voltage meter
(voltmeter). Attach the voltmeter leads to the positive and negative terminals of
the battery. To check a battery surface voltage, remove the positive terminal protective
cover and connect the +positive side meter lead (red) to the positive side battery
terminal then connect the - negative (black) side meter lead to the negative battery
terminal. With the vehicle not running and sitting over night the battery voltage
should be between 12.4 and 12.6 volts. To test the system without a volt meter activate
the headlights, if they illuminate brightly the electrical system probably has sufficient
voltage. If the headlights are dim or not working the battery charge is either low
or the battery has failed and needs replacing.
Checking Battery Voltage
Starter Voltage-Amperage Draw Test - Turn the headlights on
and observe, activate the ignition key to crank the engine over. If the headlights
stay bright the electrical circuit is not connected, therefore no voltage drop.
A popular reason for this is the winding inside the starter has shorted or the starter
armature brushes have worn out and replacement is recommended. If headlights dim
way down this indicates your battery is weak and needs either replacement or recharge.
As a rule of thumb, a typical car battery will last three to four years before replacement
is needed.
Check Neutral Safety Switch-Clutch Safety Switch - A neutral
or clutch safety switch is used to disengage the electrical circuit from the ignition
key to the starter motor as a safety device. Automatic transmission vehicle gear
selector needs to be either in park or neutral before the engine will crank (Make
sure the parking brake is activated). If the gear selector is in any of the other
gear sections the engine will not crank over. A standard transmission vehicle the
clutch pedal needs to be fully depressed before the engine will crank over. To test
this circuit an automotive test light is needed. Attach one end of the test light
to engine ground and the other end to the starter trigger terminal of the starter
solenoid (small wire). The test light should illuminate when the ignition switch
is activated (Crank engine over). If the test light illuminates the starter motor/solenoid
has failed and needs to be replaced. If the test light does not illuminate suspect
a neutral safety switch or clutch safety switch. A wiring diagram is needed to trace
power from the ignition switch
through the safety switch and down to the starter solenoid. Replace failed components
as needed and recheck system.
Starter Solenoid (appearance may vary)
Testing Anti Theft Device - Some cars have an anti theft system
that will not allow the starter to operate. If this system malfunctions the car
will not crank over even after the alarm has been disabled. To test this system,
observe the "Security" light on the dash or instrument cluster. If this light flashes
while the key is being activated the security system is in failsafe mode. If you
have an after market alarm system in your car and you think it may be the problem
locate the main system interrupted relay and bypass main control circuit. If car
cranks over the alarm system has failed and replacement is needed.
Check for Internal Engine Damage - If your
engine has had a major malfunction
it will not turn over. To check for this condition install a socket wrench on the
front crankshaft bolt, then try to rotate. The engine will turn with a certain degree
of difficulty but it should rotate a full 360 degrees (clockwise). If the engine
doesn't turn disassembly is required, repair as needed and reassemble.
If further assistance is needed, our certified car repair technicians are ready
to answer your car questions.
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