Make sure your alternator’s positive and negative terminals are clean. Put the multimeter’s black cable to the negative terminal and the red cable to the positive terminal. Look for an ideal alternator reading of around 12.6. Start the car, and look for a reading of between 14.2 and 14.7.
How do you check if your alternator is bad?
7 Signs of a Failing Alternator
- Dim or Overly Bright Lights. …
- Dead Battery. …
- Slow or Malfunctioning Accessories. …
- Trouble Starting or Frequent Stalling. …
- Growling or Whining Noises. …
- Smell of Burning Rubber or Wires. …
- Battery Warning Light on Dash.
Can you test an alternator without removing it?
If you’re tempted to test an alternator by disconnecting the negative battery cable, don’t do it. A good alternator may indeed keep the engine running without the negative cable, but this was never a good test. In the pre-computer days, you could pull it off without damaging anything.
Is there a way to test an alternator?
Place the red lead of the voltmeter to the positive battery terminal and the black lead to the negative terminal. Avoid touching your skin to the battery. Read the voltmeter. If the battery reads above 12.2 volts, it has enough juice to start the alternator, which can then be tested with the voltmeter.
How do I know if I need a new battery or alternator?
If your car’s battery isn’t holding a charge, you have a problem with your alternator or battery. If your battery can start your vehicle but dies as the car runs, you have a faulty alternator. If your battery has been charged and can’t start your vehicle, it’s a battery issue.
What can damage an alternator?
Driving a vehicle through water that is deep enough to splash or flood the alternator can damage the alternator shaft bearings and possibly the brushes and electronics inside the unit as well. Water can also cause corrosion that over time will damage the wiring and bearings inside the alternator.
How can I test if my alternator is bad at home?
A battery test is easy to perform and can be done at home. First, open the hood and start the car. While the engine is running, remove the negative cable from the battery. If the vehicle stalls or dies, the alternator is likely bad.
How long do alternators last?
around 7-10 years
How Long Does an Alternator Last? An alternator should last between 80,000 to 150,000 miles, which usually means around 7-10 years.
How do I know if my alternator is draining my battery?
But the easiest way is to check for AC currents at the battery. So what you want to do with the engine running. So the alternator is running is set your multimeter to look for AC voltage.
How do I test my alternator without a multimeter?
Here. If the alternator is charging then the motor will stay running. And if it's not charging the motor will die and we all know it takes electricity for these course runs.
Can a bad alternator destroy a new battery?
If you take your vehicle to an auto parts store they may give you a new battery for a few hundred dollars, without running any tests. Don’t make this mistake! A faulty alternator could ruin a perfectly healthy battery, which would put you further back from a solution than where you started.
Can AutoZone test your alternator?
Every AutoZone in the USA will check your alternator, starter, or battery at no charge.
Can O’Reilly test an alternator?
Your local O’Reilly will test your alternator for free on or off your vehicle so you can know for sure whether or not that’s the problem with your vehicle.
Does Advance Auto Parts do free alternator testing?
We will test your battery, starter, and alternator to make sure your vehicle is starting and charging for even the longest road trip. We can test your battery, starter, or alternator on or off the vehicle. This is a free service for all customers.
How much will it cost to replace an alternator?
Typically, it costs between $400-$600 to replace a faulty alternator with parts and labour. However, this price usually reflects a remanufactured alternator. New alternators can run you approximately $500 to $1000, again, depending on the type of vehicle you have.
Is it worth replacing an alternator?
It’s usually a better idea to replace the alternator entirely if it is malfunctioning. While new ones can be spendy, they are usually a better choice than remanufactured or rebuilt options. Those probably won’t last as long as a new one since the mechanical parts have miles on them already.
What causes alternator to fail?
Alternators have a number of moving parts, so as they get dirty and are subjected to extreme temperatures, those internal components can wear out, causing the alternator to go bad. One of the most common problems you’re likely to experience with an alternator is a failure in the bearings.