Battery light came on all of a sudden one day

FELECIA ARNOLD

MEMBER
2000 MAZDA MPV
2.5L
V6
2WD
AUTOMATIC
250,000 MILES

I had the alternator removed and rebuilt. The alternator was put back on and the battery light is still on. Now let me add a few things. The person I had working on the vehicle did several things wrong. First they removed the positive side of the terminal on battery twice before removing negative terminal. When the terminal was put back on it arced. I also had him remove a stereo system he added with a huge amp and speakers. The car will start and run but the battery light comes off and on. What can this be?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Welcome to 2CarPros.

We have one of two issues. First, the alternator still doesn't work. Or, there could be an issue with wiring, a fuse, the power-train control module and so on.

Lets start with determining if the alternator is actually charging. Follow this link for checking the alternator:

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

Here are a few links to help with testing the alternator:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

If the alternator tests good, then I need you to check related fuses. Here are links to help:

https://www.2carpros.com/articles/how-a-car-fuse-works

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

I attached a couple pictures below to help with identifying the fuses you need to check. I circled the ones I need you to inspect.

Now, if the fuses are good, the wiring is properly connected at the alternator, and the alternator isn't charging, I need you to remove the alternator and have it bench tested at a parts store. Most will do it for free.

Here are the directions for removing and replacing the alt. The remaining pics correlate with the directions. Also, when you disconnect a battery, start with the negative terminal.

______________________

2000 Mazda Truck MPV DX V6-2.5L DOHC
Removal/Installation
Vehicle Starting and Charging Charging System Alternator Service and Repair Procedures Removal/Installation
REMOVAL/INSTALLATION
WARNING: 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 battery before performing the following operation.

1. Disconnect the negative battery cable.
2. Remove the drive belt.
3. Remove the front pipe.
4. Remove the joint shaft.

pic 3

5. Remove in the order indicated in the table.
6. Install in the reverse order of removal.

______________________

Let me know what you find or if you have questions, let me know.

Take care,
Joe

Images (Click to make bigger)