Is AutoZone alternator test reliable?

Before heading to the repair shop, I stopped by AutoZone on my way home. In 5 minutes, they hooked up their equipment and tested the battery load. They advised the alternator was toast – confirmed that with the repair shop the next day. Short answer – Yes, they’re accurate.

Can AutoZone diagnose a bad alternator?

Every AutoZone in the USA will check your alternator, starter, or battery at no charge.

Can an alternator test good but still be bad?

The only way to know if an alternator is good or bad is to bench test it on an alternator test stand. … If an alternator can produce normal voltage and current during a bench test, the problem is not the alternator but something else on the vehicle.

How do I check if my alternator is good?

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  1. Get a multimeter.
  2. Set your multimeter to DCV (DC Volts) above 15.
  3. Make sure your alternator’s positive and negative terminals are clean.
  4. Put the multimeter’s black cable to the negative terminal and the red cable to the positive terminal.
  5. Look for an ideal alternator reading of around 12.6.
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What’s the easiest way to tell if your alternator is bad?

7 Signs of a Failing Alternator

  1. Dim or Overly Bright Lights. …
  2. Dead Battery. …
  3. Slow or Malfunctioning Accessories. …
  4. Trouble Starting or Frequent Stalling. …
  5. Growling or Whining Noises. …
  6. Smell of Burning Rubber or Wires. …
  7. Battery Warning Light on Dash.

Can you test an alternator without removing it?

Many auto parts stores will test alternators, starters and batteries for free, though you will have to remove the alternator to have it tested at an auto parts store. Once connected to a terminal, an alternator should test between 12 and 13.5 volts.

Can an alternator be tested off the car?

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.

Can you jumpstart a car with a bad alternator?

While jumpstarting a vehicle with a bad alternator may technically be possible, do not leave jumper cables connected between vehicles longer than necessary as it can result in damage to sensitive electronics.

How do you check if it’s your battery or alternator?

If your engine won’t turn over or takes far longer than usual, it’s time to grab the jumper cables and attempt a jump-start. If your engine starts and stays running but won’t start again later, it’s likely a battery problem. If your vehicle immediately stalls, it’s probably a bad alternator.

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How do I know if it’s my battery or alternator?

Starting and running an engine, in its simplest form, is a three-step process. … If the engine starts but dies immediately, your alternator probably isn’t keeping your battery charged. If a jump starts and keeps your car running, but the car can’t start again off of its own power, a dead battery is likely your answer.