A heavy-duty truck equipped with a 24 V starting system experiences slow cranking, especially during cold weather. The technician measures 22 V across the battery terminals during cranking, and the starter motor draws 500 A. Battery connections are clean and tight. Which of the following is the most likely cause of the slow cranking?

Question: A heavy-duty truck equipped with a 24 V starting system experiences slow cranking, especially during cold weather. The technician measures 22 V across the battery terminals during cranking, and the starter motor draws 500 A. Battery connections are clean and tight. Which of the following is the most likely cause of the slow cranking?

Answer options: ✅ High resistance in the battery cables or connections.

• A short circuit within the starter motor windings.
• An overcharged battery resulting in reduced capacity.
• A faulty alternator producing insufficient charging voltage.

Correct answer: High resistance in the battery cables or connections.

Explanation: A voltage drop from a nominal 24 V to 22 V during a heavy 500 A draw indicates excessive resistance in the circuit, most commonly in the battery cables or connections. A short circuit in the starter motor would likely cause a much higher current draw and possibly no cranking. An overcharged battery would not typically cause slow cranking, and a faulty alternator would primarily affect charging, not cranking performance, unless the battery was undercharged as a result, which is not indicated by the measured 22 V.