A failed alternator typically shows a flickering dashboard battery light, dim or overly bright headlights, strange whirling or grinding noises, or a weak battery that rapidly dies.
Failing Alternator Symptoms
- Dim or flickering lights: Your headlights or interior lights appear dim or change brightness with engine speed.
- Over-bright lights: Your headlights or interior lights appear very bright and generate excessive heat.
- Weak audio system: The stereo output sounds weaker or cuts out intermittently.
- Audio system noise: Hums or buzzes, and the sound changes with engine speed.
- Dashboard warning light: You may see a battery-shaped warning light on your dashboard.
- Burning electrical smell: A strange odor could indicate alternator problems.
- Battery acid smell: alternator over-charging will cause the battery acid to boil and off-gas. The acid will damage the area surrounding the battery. The gas produced by a boiling battery is explosive and a serious safety hazard. Do not correct jumper cables if the battery is over-charging!
- Battery constantly dying: Even after replacement, the battery drains quickly.
- Engine stalls after the jump cables are removed.
- Grinding or whining noise: You hear unusual sounds from under the hood that change pitch as engine speed varies.
Why This Happens
Alternators wear out with age or suffer a part failure. Alternator power output can gradually decline or suddenly stop. A voltage regulator failure is a common alternator problem. If the vehicle has low mileage, the regulator can be replaced. If the vehicle is older and has high mileage, the best repair is an alternator replacement with a remanufactured or new unit.
A battery failure can cause an alternator failure. A bad battery with high resistance will overload the alternator and cause it to overheat and fail.
A cooling system problem that causes high under-hood temperatures can overheat the alternator, causing it to fail prematurely.
What Needs To Be Done
An alternator issue is not a roadside repair or a problem that can be ignored. If repair is delayed, the battery will be damaged, and the vehicle will be unreliable.
Alternator failure is a problem that will require an auto repair shop to diagnose and repair the charging system. The technician will need to charge and test the battery; check and clean the battery terminals and cable connections; check the vehicle's computer for error codes; test the alternator's output; determine the cause of the alternator problem; and repair the electrical problem or replace the alternator. The battery may also need to be replaced.
What Can I Do
If your vehicle has an alternator problem, you have two options:
- Your first option, if the battery is in good condition, is to fully charge the battery, which should give you enough time to drive a short distance to a repair shop. The distance you can drive before the engine quits can be maximized by limiting the use of accessories such as the air conditioner, heater, windshield wipers, headlights, and radio.
- Your second option is to have your vehicle towed to a repair shop such as Hoover Street Auto Repair in Ann Arbor, MI.
Recommended Towing Company
24/7 Auto Towing And Roadside Assistance in Ann Arbor
Your best decision is to have your vehicle towed to Hoover Street Auto Repair. Getting your vehicle to us as quickly as possible increases the chance of a same-day diagnosis and repair.
- Our recommended towing company in Ann Arbor is Brewer’s Towing: 734-662-9715
- You can also use AAA Roadside Assistance: 800-222-4357
Both towing services know our location in Ann Arbor and can assist you with dropping off your vehicle and keys so that we get an early start when we open.
Recommended Auto Electrical Repair Shop
Hoover Street Auto Repair is an Ann Arbor, MI auto repair shop.
Hoover Street Auto Repair provides alternator testing and repair for Asian import and domestic autos in the Ann Arbor area.