Factors that can disable starting the engine are:
1. if automatic transmission, should be in Park or Neutral. In some instances, you may need to move the shift lever a couple of time to trigger the hidden switch;
2. anti-theft/alarm system. You may need to check the connectors, disable or the electronic key and try several times;
3. Starting system - the issue is might be with the starter system. The starter system is initiated
at the ignition switch when the key is turned to start. At this point,
the ignition switch then provides +12VDC to a starter relay (if the vehicle has got one) or straight to the starting solenoid. The relay
is but a remote switch with slightly higher amperage capacity. The
starter relay then engages and supplies +12VDC to the staring solenoid.
The starting solenoid then performs two (2) functions. It provides the
switching action (hundreds amps) from the battery heavy cable to the
actual starter motor. The solenoid likewise pushes a small pinion gear
along the shaft of the starter motor to engage the ring gear. The ring
gear is of course on the edge of the flywheel which in turn is attached
to the crankshaft.
Starter system problems could be corrected by:
1. check battery, battery cables and connections;
2. charge the battery if required;
3. clean brushes and guides of brush holders of the starter motor;
4. clean the commutator and commutator segments;
5. check/replace the armature or field coils if determined to be defective;
6. in some extreme cases it could be the drive pinion or the flywheel gear ring is defective.
7. often it is the big switch that the solenoid activates that looses contacts causing no +12V internally to the motor.
Most likely would be a defective starter relay or the IGN switch
itself. Relative to this, you might try and check the
connectors/terminals and electrical joints.
In the picture below, the upper portion is the starter solenoid while the one below it is the actual starter.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
Good luck and kind regards.
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