A technician is diagnosing a vehicle with an intermittent 'no crank' condition. When the ignition key is turned to the 'START' position, the technician observes that the starter motor does not engage, but a distinct 'click' is heard from the starter solenoid. Further testing reveals that battery voltage is 12.5V, and the voltage at the starter motor's large battery cable terminal (B+ terminal) is 12.4V. What is the MOST likely cause of this condition?
- AAn open circuit in the starter motor winding.
- BWorn or pitted starter solenoid contacts.
- CAn open circuit in the starter motor's main power feed.
- DA discharged battery.
Show answer & explanationAnswer & explanation
Correct answer: B. Worn or pitted starter solenoid contacts.
The 'click' from the starter solenoid indicates that the control circuit (ignition switch, relay, S-terminal) is working correctly and the solenoid is attempting to engage. Good battery voltage (12.5V) and 12.4V at the main B+ terminal of the starter confirm ample power *to* the starter. If the solenoid clicks but the motor doesn't crank, and power is present at the starter, it strongly suggests that the solenoid's internal contacts are worn or pitted, preventing the high current from reaching the starter motor windings, even though the solenoid plunger moves.
Why the other options are wrong
- A. An open circuit in the starter motor winding would prevent cranking, but the solenoid would still allow power through to the winding, and the 'click' would be heard. However, the issue is that the power isn't *getting* to the winding due to the solenoid's internal failure to connect it.
- C. The 12.4V at the starter motor's B+ terminal indicates the main power feed is good, so there's no open circuit there.
- D. 12.5V is a healthy battery voltage, ruling out a discharged battery.
Starter Solenoid Click, No Crank
When a starter solenoid clicks but the starter motor does not crank, it typically indicates worn or pitted internal contacts within the solenoid, which prevents the high current flow to the starter motor windings, even though the solenoid plunger engages.
- Solenoid control circuit is working (it clicks).
- Main battery power is reaching the starter/solenoid.
- Internal solenoid failure to pass high current is the cause.
Memory trick: Click but no crank, solenoid's tired, a high-current tank.