Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsStarting System Diagnosis and RepairMedium
A vehicle owner reports that their vehicle starts normally most of the time, but occasionally, when the ignition key is turned to the START position, nothing happens – no crank, no click, and all dashboard lights remain on brightly. The battery has been recently replaced. Which component is the most likely cause of this intermittent 'no-crank, no-click' condition?
- AAn intermittently open circuit in the main battery cable
- BA faulty neutral safety switch
- CA failing starter motor armature
- DA seized starter motor solenoid plunger
Show answer & explanationAnswer & explanation
Correct answer: B. A faulty neutral safety switch
An intermittent 'no-crank, no-click' condition, especially when other electrical systems appear functional, strongly suggests an issue with the control circuit that prevents the solenoid from receiving power. The neutral safety switch often fails intermittently, preventing starter engagement unless it's in a precise position.
Why the other options are wrong
- A. An intermittently open circuit in the main battery cable would likely affect all electrical systems or cause slow cranking, and could potentially result in a 'click' if the solenoid receives some power.
- C. A failing starter motor armature would typically result in a 'click' but no crank, or slow cranking, not a complete 'no-crank, no-click'.
- D. A seized starter motor solenoid plunger would likely cause a 'click' but no crank, as the solenoid receives power but cannot physically move to engage the starter.
Neutral Safety Switch
A safety device that prevents the starter motor from engaging unless the transmission is in Park or Neutral.
- Located on the transmission or shifter assembly.
- Can cause 'no-crank, no-click' if faulty or misadjusted.
- Part of the starter control circuit.
Memory trick: When 'No-Go' and 'No-Show', check the 'Neutral' flow.