Battery Light Stays On?

FlannelBoy711

Member
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2002 Mazda Protege 5
Ok I have a scenario, recently my car broke down, the lights inside the car were dim and everytime I turned the headlights on the car would turn off. So I took it to a shop got it looked at, they put 2 alternators in (1 used/1 new) still had a problem. They give me two options: 1: Drive around with a new alternator but the battery light inside the car will stay on so you will not know when a problem is happening, the other is taking it to the Mazda dealership and having them replace the CPU($$$.$$). The thing is the battery light has always shown up for me since I installed my Ebay SRI. Is there any intake I can buy that will stop the light from showing up? Any wire I can mess with to have the light stop turning on? Any post would be greatly appreciated.
 
The intake has nothing to do with the battery light. You can test by putting the old one back on, takes 10 minutes.

It sounds like you've got an electrical problem. Bad ground etc. You may have bumped something when you installed the intake. I'd look at all the wires & connections around the intake and battery, sounds like something is out of place or touching something it shouldn't be.

Or your battery has gone bad and is not taking a charge.
 
I was talking to my old mechanic back where I used to live and he told me that the CPU and the alternator are not together, meaning they dont depend on one another.The battery is new and the alternator that was just put in is new. My new mechanic says one of the components in the CPU might be fried and has to be replaced.
 
FlannelBoy711 said:
I was talking to my old mechanic back where I used to live and he told me that the CPU and the alternator are not together, meaning they dont depend on one another.The battery is new and the alternator that was just put in is new. My new mechanic says one of the components in the CPU might be fried and has to be replaced.

You gotta replace the PCM. There's no getting around it. The alternator will not charge the battery unless is is getting the proper signal from the PCM. I've seen this in several Proteges before. I was a Mazda Tech for 2 years.

Sean
 
What Sean said... New ECU time man. If you're staying N/A get the MP3 ECU... Pick up some power gains.
 
not sure what shop up here you took it to, but give Sal's a shot. They know their stuff.

Sal's Automotive
3650 NW 97th Blvd
Gainesville, FL

<label>Phone:</label> (352) 332-4338
 
Question, is there a seperate PCM I can buy? Or do I have to buy a whole ECU? And the whole MP3 ECU Ive heard is just bull, I know it doesn't had HP right away, but can it eventually if you make the right upgrades?
 
RaiderMP5 said:
not sure what shop up here you took it to, but give Sal's a shot. They know their stuff.

Sal's Automotive
3650 NW 97th Blvd
Gainesville, FL

<label>Phone:</label> (352) 332-4338

I went to Computa Tune on SW 34th street, they told me everything and never charged me for anything extra, ( they used 2 different alternators)
 
FlannelBoy711 said:
Question, is there a seperate PCM I can buy? Or do I have to buy a whole ECU? And the whole MP3 ECU Ive heard is just bull, I know it doesn't had HP right away, but can it eventually if you make the right upgrades?

It wil ladd power right away just by plugging it in cause it has more advanced timing and gets rid ofthe VTCS. You should remove it from your manifold though...
 
hey, i'm new to the board and looking for a little help.
i have a similar problem with my '00 ES. after sitting overnight or all day at work, upon start-up the battery light comes on. after driving 5 or 10 miles the battery light will go out.

i've checked battery voltage without a load (12.5) and also checked voltage at battery with the car running (13.8) so i think the alternator is charging and the battery is going bad. battery is only a couple of yrs old but its an Everstart(or should i say Neverstart) from Wally World.

i am going to have the battery load tested and go from there.

what do you guys think?
 
thrasher said:
The intake has nothing to do with the battery light. You can test by putting the old one back on, takes 10 minutes.

It sounds like you've got an electrical problem. Bad ground etc. You may have bumped something when you installed the intake. I'd look at all the wires & connections around the intake and battery, sounds like something is out of place or touching something it shouldn't be.

Or your battery has gone bad and is not taking a charge.
THis is not true. Our pcms tell the alternator how to charge the battery. Its one of the reasons we cant run a true standalone.

Edit: just read rest of it, what sean said :)
 
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