Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsGeneral Electrical/Electronic System DiagnosisHard
A technician is diagnosing an intermittent starting issue. The starter motor occasionally cranks normally, but sometimes there is a 'click' from the starter solenoid and no cranking. Battery voltage tests good, and a voltage drop test on the starter power cable shows minimal drop during cranking when it does work. What is the MOST likely cause of the 'click, no crank' symptom?
- ALow battery voltage or excessive parasitic drain
- BAn intermittent open in the starter solenoid's high-current contacts
- CA worn starter motor commutator or brushes
- DA faulty battery ground cable connection
Show answer & explanationAnswer & explanation
Correct answer: B. An intermittent open in the starter solenoid's high-current contacts
A 'click, no crank' symptom, especially with good battery voltage and minimal voltage drop on the main power cable, points to the starter solenoid. The click indicates the control circuit (pull-in coil) is working, but if the high-current contacts are intermittently open or burnt, the main power cannot reach the starter motor windings.
Why the other options are wrong
- A. Low battery voltage would usually result in a rapid 'chattering' click from the solenoid or slow cranking, not a single strong click with no cranking.
- C. Worn commutator or brushes would typically cause slow cranking or no cranking, but the solenoid would still engage and attempt to spin the motor. The 'click' without cranking is specifically a solenoid power delivery issue.
- D. A faulty battery ground cable would cause high voltage drop and affect all starter operation, likely resulting in no click or a weak click, not an intermittent click-no-crank.
Starter Solenoid Contacts
High-current electrical contacts within the starter solenoid that, when closed, connect main battery power directly to the starter motor windings.
- Handle very high current
- Can wear or become pitted over time
- Failure leads to 'click, no crank' symptom
Memory trick: Solenoid clicks, but the motor just sticks.