Mazda3 Alternator Problems

Without the alternator, your power supply would diminish until the vehicle died. Don't let the alternator go bad while you're driving down the road, get ahead of the problem to detect alternator problems now. Here are some of the warning signs that you have an alternator problem in your Mazda3 and how to replace it when it comes time.

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Mazda3 alt

Lights Dim

Because the alternator is part of the electrical system, as it starts to go bad, the lights will start to dim. If it is bad, it can no longer send power to the electronic parts in your car.

Warning Light

Your car may have a warning light associated with the alternator to let you know that there is a problem. The light looks like a battery or may say ALT or GEN. It may only come on if you are powering several electrical parts at once.


A dead or weak battery may be a sign of a bad alternator. Batteries do die, but the alternator should keep the battery-powered if the battery still has a lot of life left in it. You may test the battery by putting it on a charger and starting the car. If the battery is bad, you will see a change in the lights. If the alternator is bad, the vehicle will be difficult to start even with a fully charged battery.

Strange Smells

The alternator is belt-driven, and if the belt is not working, there can be excess friction. This will result in a burning rubber smell. A smell like that you find in an electrical fire may also be due to belt slippage. Tighten the belt on the pulley and that should take care of the problem.

Strange Sounds

The alternator has a lot of spinning parts that generated a current, so if one of these spinning parts is not working, you may hear a whining or grinding noise. Worn-out bearings will be particularly noisy. The bushings can also make a noise. You may need to replace the entire unit.

Visual Inspection

Look under the hood for loose or worn belts that are connected to the alternator. You will also be able to determine if any of the belts are too tight. Replace worn parts or correct the tension in the belts.

Alternator Replacement

You may need a new alternator, and if that is the case, here are the installation instructions. You will need to jack up the vehicle unless you have access to a lift.

  1. Park your Mazda on a flat, dry surface and use the jack and jack stands to lift the front of the vehicle. Place a wheel chock behind the rear wheel. If you do not know where your lift points are, then consult your owner’s manual for their location and the location of where you place the jack stands.
  2. Disconnect the negative terminal from the battery.
  3. Take off the engine cover to give you access to the engine compartment.
  4. Use a 14mm wrench on the gold-colored bolt in the center of the tensioner pulley. Push the bolt backward towards your firewall. This will pivot the entire pulley backward and take the tension off the drive belt.
  5. Loosen the belt from the alternator.
  6. Take the splash shield off from under the vehicle. It is held in place with bolts.
  7. Find the mounting bolts for the alternator. There are three of them accessed from the bottom and one from the top. They are 12mm bolts.
  8. Put the new alternator on the vehicle, and make sure that the longer bolts go on the bottom.
  9. Reverse the order of the steps for putting your vehicle back together. Make sure that the drive belt is properly seated on all of the pulleys.

This should take care of the problems you are having with your alternator. Start your vehicle and check for lights that dim or other signs of further electrical problems. If you run into problems or this does not solve your problem, you may want to contact your local Mazda dealership for assistance. You can also take a look at this Mazda 3 parts and accessories guide.