Question about 2004 Mazda 6

2 Answers

Mazda 6 alternator replaced, now battery light comes on, battery tests fine. Bad alternator??

Posted by on

  • runnerlady Aug 24, 2010

    Would like a more specific answer. We are taking the car to a mechanic this morning. What should we expect to be checked on the car and what are the possible causes of the problem?


2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Mazda Master
  • 2,019 Answers

First of all, the "battery light" has nothing much to do with the battery. In general it means no alternator output. But that does not have to mean the alternator is bad.
But you did not have the battery and alternator properly tested in the first place before just replacing it.

Before anything, make sure battery terminals are clean and greased.

What you need to do is buy a voltmeter. They sell one for $3 at Harbor Freight.
First you check battery voltage with engine off.
It should read about 12.5 volts.
If not, then charge battery.

Then you need to tell if something is draining all the time.
Remove one battery terminal clamp and put a test light between wire clamp and battery terminal.
Light should not light up.
If it does, something is on all the time and draining the battery.
Find and fix by disconnecting things one at a time until found.
(make sure you have radio code before disconnecting battery, if radio has security)

Then reconnect battery terminals and start engine.
When you rev engine, it should go from 12.5 to over 14 volts.
If it does nothing, then alternator not putting out.
Check alternator ground, input voltage on small wire, and output large wire connected properly.

You still could have a short that is draining, but the best thing to do is to take alternator out and have tested at the alternator supplier. If they agree it is bad, they will give you a new one under warranty. But make sure wires from alternator not rubbed through or melted anywhere and shorting out.

Posted on Aug 24, 2010

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Brigadier General:

    An expert that has over 10,000 points.

  • Master
  • 3,513 Answers

Please check the bellow links related to your query…

Let us know if you have something more to ask else please accept the solution.
Thanks for contacting

Posted on Aug 24, 2010

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

After replacing the alternator airbag light and battery light stays both lights go off and car dies.

electrical issues since replacing alternator & battery - Mazda 6 ... > Mazda6 (Atenza) > Newbie Section
Dec 24, 2010 - Exclamation Battery Light after Replacing with New Alternator ... TheBattery Light stays on after I start the vehicle. It comes up after ~2-3 secs of ...

Battery light flashing, air bag light on, after alternator pulley ...
Feb 11, 2012 - Battery light flashing, air bag light on, after alternator pulley changeTDI 101. ... Almost a week later I am driving home and the battery light flashes on, then off, .... Seat belt light stays on, no air bag light. cjharris02892, TDI 101 ...

Battery Light Due to Damaged Alternator Wire Harness ... > Problems > Ford > Crown Victoria
Battery Light Due to Damaged Alternator Connector on Ford Crown Victoria ... how can i turn off the airbag light on a 1991 crown victoria made by ford ... the battery light onreplace alt and batt light still what else can it be? thaqk. it sat for two weeks when we had snow i used my truck staqrted car light comes on and stays on.

Airbag light = bad battery - Maintenance, Recalls and T

Dec 27, 2015 | Cars & Trucks

2 Answers

2006 Mazda Tribute won't start. When I first purchased the car the fairly new-looking battery was reading low, so immediately had it replaced. Only to have the new battery weakening/battery light coming...

think u hav a bad cable from the alternator to the batt--they wear and gain resistence eating up alternators--its the red cable used to charge batt--some mechaanics just add anothr wire beside the old and it works--hav a honest guy test the old wire

Nov 03, 2013 | 2006 Mazda Tribute

1 Answer

Obd2 code p0562

Low battery charge, Battery Defective(Could have a bad cell), Loose or missing alternator drive belt, Faulty Alternator, Open or short system voltage circuit

Apr 11, 2017 | Mazda RX8 Cars & Trucks

1 Answer

2003 Mazda Tribute Battery light comes on but battery tested normal.

even though the altenator tests good, it could still either over or undercharge.The TSB (Technical Service Bulletin) specifies replacing the alternator and re-flashing the PCM.(Powertrain Control Mudule).

Jan 25, 2013 | 2003 Mazda Tribute

1 Answer

I have a 95 mazda B2300 4 cyl the battery light stays on my lights are dimeer then usual i had the alternator tested they said it was good what could the prob be

The battery light will only come on if the voltage supplied to the alternator is lower than the current battery voltage. It is either the alternator or instrument panel. I've never seen an instrument panel go bad on those. Look at the alternator, I've seen one with a motor mount that went bad and the alternator was laying on the frame grounding out the alternator.

May 13, 2011 | 1995 Mazda B-Series

1 Answer

Battery was dead, tried to boost car with cables, no charge at all, bought new battery next evening the car is completely dead...again, could it be alternator not charging?

You are probably correct on the bad alternator...Did your battery shop test the old battery? As you get your Mazda running again...(limited use with bad alternator) most parts stores can test the alternator output to confirm it is bad...Hope this helps.

Mar 21, 2011 | 2004 Mazda 6

1 Answer

2002 mazda protege5 auto battery light coming on

I'm guessing that you've tested the actual current output of the alternator then. I'm assuming that the output is between 13-14Volts at the battery when the car is running... If it's too low, then it's not charging your battery at all, too high, and it's frying your battery.... Another thing that can cause this is if you have a short in your electrical system.. that, however, will be difficult to narrow down...

Aug 12, 2009 | 2004 Mazda 6

2 Answers

2004 Mazda 6, battery light is on.

what has this got to do with the battery light coming on

May 11, 2009 | 2004 Mazda 6

2 Answers

Electricall problem w/2002 V6 mazda tribute

When that light comes on, it is indicating charging system problem which could mean alternator not charging for one reason or another like loose belt, faulty alternator, or yes, bad battery or connection at battery, for example. First & easiest thing to do is check all your connections to battery, which you've probably done, and make sure they're tight & clean. Make sure belt driving alternator is good & tight, and in good shape. Now boost the vehicle to get it going & test voltage at battery, after you take cables off. My guess is in your case, the voltage will begin to go down, indicating a bad alternator, that will need to be replaced.

Jan 17, 2009 | 2002 Mazda Tribute

Not finding what you are looking for?
2004 Mazda 6 Logo

Related Topics:

332 people viewed this question

Ask a Question

Usually answered in minutes!

Top Mazda Experts


Level 3 Expert

75822 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22156 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

8202 Answers

Are you a Mazda Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides