What to Do When the Car Alternator Is Not Generating Electricity?
3 Answers
There are many reasons why a car alternator may not generate electricity, and solutions can be tailored based on the specific cause: Causes and Solutions: If the alternator belt is broken or slipping, tighten the adjustment device or replace the belt. If there is an open circuit in the alternator output wire, check the condition of the wire and repair it if necessary. If the rotor part is stuck, manually test whether it rotates smoothly. If the coil is damaged, use a multimeter to measure the coil resistance to see if it is normal. If there is no resistance value, the coil must be rewound or the motor replaced. Testing Methods for a Non-Generating Car Alternator: Multimeter Voltage Test: Set the multimeter to the 30V DC voltage range. Connect the red probe to the alternator's "armature" terminal and the black probe to the casing. Run the engine at medium speed or higher. For a 12V electrical system, the standard voltage should be around 14V, and for a 24V electrical system, it should be around 28V. If the measured voltage matches the battery voltage, the alternator is not generating electricity. External Ammeter Test: If the car dashboard does not have an ammeter, an external DC ammeter can be used for testing. First, disconnect the wire from the alternator's "armature" terminal. Then, connect the positive terminal of a DC ammeter (with a range of about 20A) to the alternator's "armature" and the negative terminal to the disconnected wire. When the engine runs at medium speed or higher, a charging indication of 3A to 5A on the ammeter means the alternator is working normally; otherwise, it is not generating electricity. Test Lamp Method: If a multimeter or DC ammeter is not available, a car bulb can be used as a test lamp. Solder wires of appropriate length to both ends of the bulb and attach alligator clips to the ends. Before testing, disconnect the wire from the alternator's "armature" terminal. Clip one end of the test lamp to the alternator's "armature" terminal and the other end to the ground. If the bulb lights up when the engine runs at medium speed, the alternator is working normally; otherwise, it is not generating electricity.
I know all about alternators not charging! Main checks are the belt – if it's broken or too loose, the alternator stops working; also, failed diodes or a faulty regulator are common culprits. Before diving in, check if the battery warning light on the dashboard is on – that's a telltale sign. You can try restarting the car yourself and inspect the belt under the hood for damage – if it's broken or loose, replace it first. However, most times it's best not to push your luck; get a professional mechanic to diagnose it ASAP. Otherwise, the battery can drain instantly, and getting stranded mid-journey is worse. I've had to tow a car before – not only did the repair costs double, but it also wasted time. Remember: timely fixes prioritize safety, don't let small issues snowball into big trouble.
Oh no, if the alternator stops working, it's extremely dangerous! It can quickly drain the battery, and the car might suddenly stall while driving, especially on highways where rear-end collisions are likely. From my experience, once you notice difficulty starting the engine or the battery warning light stays on, pull over immediately, turn on the hazard lights, and call for a tow truck. Never push through and keep driving—not only could the car become immobile, but the battery and electronic systems might be completely ruined, leading to even costlier repairs. Make it a habit to always pay attention to dashboard warning lights; when they light up, it's no small matter. Safe driving is more important than anything—stop early and seek help early!
