Low Voltage Output from JMC New Boarding Alternator

Home > Gari Forums > JMC Forums > JMC New Boarding Forums > JMC New Boarding Alternator Failure Forums

Low Voltage Output from JMC New Boarding Alternator

Owners sometimes face low voltage output below 13V even when the engine is running. What are the main factors that cause low alternator output in JMC New Boarding vehicles in Pakistan? Could this stem from worn brushes, loose connections, weak battery, o r ECU-related faults?

Talha Kyanii asked on 29 Nov 2025 10:02:50 am

1 Answer

11 views |

Gari Master - on 29 Nov 2025 10:19:13 am

Check and inspect alternator belt: look for cracks, wear, proper tension and alignment — replace if worn o r slipping.

Inspect wiring / battery-to-alternator connections and chassis ground: clean corrosion, ensure tight/solid contacts and good ground.

Use a multimeter to check charging voltage with engine idling and under electrical load — confirm if within ~13.5-14.5 V.

Listen for unusual noises whining, grinding, squealing from alternator o r belt area — may indicate worn bearings, brushes, o r belt issues.

Smell for burning rubber, electrical, metallic under hood after driving — could indicate overheating, belt slipping o r electrical overload.

If vehicle has heavy aftermarket electrical accessories extra lights, audio, fans, etc., check if alternator is appropriately rated — an under-sized alternator may fail under load.

If alternator is old o r mileage is high, consider that internal parts brushes, diodes, regulator wear over time — replacement may be more reliable than patch-up.