If you’ve heard the word “alternator” before, there’s a solid chance you know it’s an important part of your car. But what does an alternator do? In simple terms, your alternator keeps your car battery charged so you can turn on your car and use the electronic accessories when you drive.
If you have a car alternator problem, you may find that your car will not start or stay on for much if at all, and you may also have issues or irregularities with your battery, accessories, and lights.
However, before any of these happen, you will most likely see at least one of the seven signs appearing (we will discuss in detail) regarding your alternator being faulty.
Below we will cover how to identify a faulty alternator before it leaves you on the side of the road.
7 Signs Of A Faulty Alternator
Your battery is what provides the initial electrical punch you need to start the engine. As long as the engine is running, the engine turns the alternator pulley, which keeps the battery charged. The alternator is the link between the two systems.
Since the battery can’t keep the engine and electrical accessories charged indefinitely, it relies on the alternator to convert the engine’s rotational power into electricity. If there is an issue with this charging system, you will notice one or more of the following bad alternator symptoms.
#1. Battery warning Light On Dashboard.
The battery light on your dashboard should not be confused with a battery problem, this light is meant to warn you that your car’s electrical charging system (which includes the alternator) may have a problem.
The alternator operates on an specific voltage generally between 13-14.5 volts. When the alternator fails to operate, it’s voltage can drop below these levels and cause the battery light to trigger. Depending on how hard your alternator is working, it could also trigger the battery light when it was operating above the normal voltage limit.
Depending on how much electrical load you have from your car’s accessories (headlights, wipers, stereo, etc.), you may see the battery light flicker on and off as the alternator moves in and out of its operating voltage capacity.
Although this may be an annoyance, you do not want this light flickering if the alternator is working correctly while the engine is running. It is better to have an inspection on your alternator now before you find yourself stuck on the side of the road.
#2. Dim Or Overly Bright Lights.
When either an alternator or its voltage regulator start to fail, it may send inconsistent voltage to your electrical accessories.
Generally this manifests itself as under- or over-performing equipment, such as headlights that may be either dim or excessively bright.
You may experience flickering lights, or lights that suddenly go from bright to dim and back again. Overloaded lights may also have a shorter lifespan potentially failing early, especially if the situation is not dealt with quickly.
#3. Dead Battery.
A dead battery may just be a dead battery once it reaches the end of its life after a few years of use, or perhaps you left the headlights on overnight by accident. But, a dead battery can also signal that you have an alternator issue.
A bad alternator isn’t charging the battery sufficiently while the engine is running, so the charge will deplete faster than normal.
One way to analyze a possible dead battery or bad alternator issue is to jumpstart the car. If at the jumpstart, you’ve jumpstarted the car correctly and it’s been running for a while, you’re likely looking at a battery that is due for replacement.
If the jump-started vehicle dies shortly after you disconnect the jumper cables you may not have enough power from the alternator reaching the battery.
If you have a battery that goes dead overnight or when your car is parked without the engine running, your alternator’s rectifier potentially has an issue.
An alternator makes alternating current (AC) and a car battery needs direct current (DC). If the rectifier is functioning, the AC is converted to DC by allowing the current to flow only in one direction.
But if the rectifier diode has an issue the current can flow both directions. Yup, that’s right! The alternator can potentially drain the battery!
When the diode isn’t preventing electricity from flowing back it will, when the engine is off, actually send electricity from the battery to the alternator potentially draining your car battery.
#4. Slow Or Malfunctioning Accessories.
If your alternator is not providing enough power for your car’s electrical components, you will probably start to see slow or non-functioning accessories.
This might be as simple as noticing if your power windows take longer than usual to go up or down, your seat warmers feel “off,” or maybe your speedometer and other gauges are “going crazy” while the vehicle is running. If you start seeing any of those actions, you may have an alternator problem.
Many vehicles made in the last 10-20 years might even have a priority list of equipment programmed into the car that tells the onboard computer which electrical components to cut power to first if the alternator isn’t able to provide enough electricity.
So, if you are driving around with a faulty alternator, you will most likely lose power to your radio (or other non-essential accessories) before you will lose power to your headlights.
#5. Still Having Trouble Ang Starting or Often Stalling.
Having trouble starting your engine might mean that your alternator is not providing a charge to the battery. This means that when you turn the key, all you will hear is a click and not the purr of your engine.
However, you may have a different scenario, if while driving you often stall out or are in a stall state and you notice that your battery light is illuminated, it is possible you have a situation where the control modules are not getting enough power delivered from the alternator to keep your engine running.
#6. Growling Or Whining Noises.
Cars make a variety of strange noises – some are harmless, and just odd, and others can indicate a serious mechanical condition.
If you hear what can only be described as a growl, or whining coming from under the hood, there is a very good chance that you could have alternator problems or possible issues with your drive belt and you should have this assessed by a qualified technician as soon as possible.
The growling or whining sound occurs mostly when belt that drives the alternator pulley is not aligned correctly or it is rubbing against the side of the pulley. You may also hear this noise if the bearings that turn the rotor shaft are bad.
#7. Smoking Or Burning Rubber or Chemicals.
If you smell a foul odor of burning rubber or wires, it could be an indication that the alternator is beginning to wear out. The drive belts take stress and friction and will wear out with time and possibly even emit a foul odor of burning rubber due to the belt being close to the hot engine.
Likewise, you may detect a burning odor from your alternator as a result of it being overworked, or that a wire is damaged, frayed or broken on the alternator where may detect an odor similar to that of an electrical fire.
An overworked alternator has attempted to deliver a charged to greater proportion than it was made to and, for all intent and purpose, the wires get heated up to an unsafe temperature, and when a wire is frayed or damaged it creates resistance to flow of electricity, hence getting hot enough to smell the foul odor of burning rubber.