Battery light turning on and off

Hi,

Was the alternator checked when the light was on indicating a problem? It could be working on and off.

I attached a pic below which is a schematic of the charging system. I circled one fuse I need you to check and make sure it is tight and not corroded. Also, note that two wires run to the power-train control module. Make sure that connection is tight and clean as well.

Also, the regulator is built into the alternator. It could be going bad as well. I attached a pic and circled it for you. See pic 2

If you find that the connections are all in good condition, I need you to try a test at home. All you will need is a volt meter or a multi meter. I want to know what the output of the alternator actually is. Follow this link:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Do these things and let me know what you find. Also, let me know if the battery is going dead.

Take care,
Joe

Hi,

I have to be honest, I really feel the alternator needs replaced. I suspect it was tested by the parts store when the light was off.

Here is a link that shows in general how one is replaced:

https://www.2carpros.com/articles/how-to-replace-an-alternator

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Here are the directions specific to your vehicle. The attached pics correlate with the directions.

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2010 Mazda 6 L4-2.5L
Removal and Replacement
Vehicle Starting and Charging Charging System Alternator Service and Repair Removal and Replacement
REMOVAL AND REPLACEMENT
GENERATOR REMOVAL/INSTALLATION [L5]

WARNING:
- Remove and install all parts when the engine is cold, otherwise they can cause severe burns or serious injury.

- When the battery cables are connected, touching the vehicle body with generator terminal B will generate sparks. This can cause personal injury, fire, and damage to the electrical components. Always disconnect the negative battery cable before performing the following operation.

CAUTION:
- The generator can be damaged by the heat from the exhaust manifold. Make sure the generator duct is installed securely.

1. Disconnect the negative battery cable.

2. Remove the plug hole plate. See: Access Cover, Engine > Removal and Replacement > Plug Hole Plate Removal/Installation

3. Remove the aerodynamic under cover No.2. See: Splash Guard > Removal and Replacement > Aerodynamic Under Cover No.2 Removal/Installation

4. Remove the drive belt. See: Drive Belt > Removal and Replacement

5. Remove in the order indicated in the table.

6. Install in the reverse order of removal.

pic 1

pic 2

Generator Duct Removal Note

1. Remove the generator duct from above the engine compartment.

Generator Removal Note

1. Remove the generator from above the engine compartment.

pic 3

Generator Installation Note

1. Tighten bolt A temporarily.

2. Tighten bolt B, C to the specified tightening torque.

3. Tighten bolt A to the specified tightening torque.

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Let me know if this helps or if you have other questions.

Joe

How did you have the alternator checked? Was it load tested? If so then we need to load test the battery as well.

https://www.2carpros.com/articles/car-battery-load-test

https://www.2carpros.com/articles/how-to-check-a-car-alternator

This light is just telling you that the charging or overall state of charge is below threshold. This could be the alternator, battery, loose belt (as you have suspected) or the voltage regulator is failing not allowing the alternator to charge properly. This is why it is important to be sure it is tested properly. The voltage regulator is most likely the cause of this.

Let me know and we can go from there. Thanks

If it works when you move the wires, either there is a bad connection when it connects or you are moving something in the alternator. Also, check the wiring to the alternator. I have seen the wiring under the insulation break. See if it feel like there are any soft spots. Also, make sure the connectors are clean and tight, and free of corrosion.

Let me know.
Joe