2000 Alero not charging, new battery and alternator

[Marty_Brownell]

Hi all,

My wifes friend came over today with her 2000 Alero 2.4L which died in our driveway. I checked it out for her and was able to determine that it wasn't charging. She just had the battery replaced.

I checked the alternator and it seemed to be running at only 3volts so I replaced it. The new one did the same time... starts at 15 Volts and then drops to 3.

I am not familiar with this car but since it is sitting in my garage I figure I will try to help her out.

Electrical lines to battery and alternator seem fine, no corrosion and no loose or frayed connections.
Anyone got any suggestions?

Thank you

[xeroinfinity]

Welcome to AF !

Could be the defective drivebelt , or A faulty regulator.
Suppose thier could also be a short somewhere causing the battery to drain.

Also double check the plug on the alternator that the pins are not bent or damaged.

Hope that helps.

[Marty_Brownell]

Originally Posted by xeroinfinity

Welcome to AF !

Could be the defective drivebelt , or A faulty regulator.
Suppose thier could also be a short somewhere causing the battery to drain.

Also double check the plug on the alternator that the pins are not bent or damaged.

Hope that helps.

Thanks. Drivebelt looked good, although I will double check again. The pins on both alternators look okay as well.

I am starting to seriously consider the Voltage regulator. I am not sure where it is located on this car though. I am going to try to get a manual today. When she revs the engine the voltage actually drops.

Thanks again.

[Marty_Brownell]

Well I checked all connections, and charged the battery with a charger.

Alternator is reading 14-15 Volts.

Battery is still dying. It just isn't charging.

Tomorrow I will call Oldsmobile and ask if they have any recommendations. I also bought an OBDII reader, the only code is a random misfire code.

[xeroinfinity]

Where did you purchase the alternator?
What is the voltages of the battery with the car off and On ?

It very well could be a defective alternator out of the box,
as the voltage reg in built into it.

And If the alternator was bad for a long time,
chances are the battery has developed a dead cell and is not holding a charge.

[Marty_Brownell]

Originally Posted by xeroinfinity

Where did you purchase the alternator?
What is the voltages of the battery with the car off and On ?

It very well could be a defective alternator out of the box,
as the voltage reg in built into it.

And If the alternator was bad for a long time,
chances are the battery has developed a dead cell and is not holding a charge.

Thanks for the reply. The battery seems to hold a charge okay, I charged it over night yesterday with a charger and it was around 12 volts. I left it all day and checked it when I came home and it was still around 12.

I am guessing here but... from the alternator, where does the line lead to? I trace it to a wiring harness which snakes through the engine, but not directly back to the battery. Could there be a componant between the alternator and the battery causing the problem?

[xeroinfinity]

If the battery is only showing 12 volts its bad.
SHould be 13+ volts without the car running.

Should read 14+volts with engine running.

[Marty_Brownell]

Originally Posted by xeroinfinity

If the battery is only showing 12 volts its bad.
SHould be 13+ volts without the car running.

Should read 14+volts with engine running.

I just spoke with Oldsmobile. They said it is very possible that it is the PCM. A bad PCM could cause the strange voltages etc since it controls the voltage regulator.

The 12V might be more because I had a trickle charger on the battery and it just wasn't enough time. I will try to test the PCM tonight.

[BNaylor]

It is possible but I'd take what you were told with a grain of salt. Unlike certain autos like some Chryslers where the PCM module totally controls the voltage regulator the Delcotron CS130D (105 amp) alternator is a complete charging system in itself. The voltage regulator is contained in the alternator. The PCM does monitor alternator/regulator output and will give a battery/charging idiot light if something is not right. It will compare the 12 volts inputted as PCM sense.

Are you sure the prior alternator did not damage the battery before it was replaced. Did you get the battery tested separately from the charging system? Also, what brand alternator was used?

[Marty_Brownell]

Originally Posted by bnaylor

It is possible but I'd take what you were told with a grain of salt. Unlike certain autos like some Chryslers where the PCM module totally controls the voltage regulator the Delcotron CS130D (105 amp) alternator is a complete charging system in itself. The voltage regulator is contained in the alternator. The PCM does monitor alternator/regulator output and will give a battery/charging idiot light if something is not right. It will compare the 12 volts inputted as PCM sense.

Are you sure the prior alternator did not damage the battery before it was replaced. Did you get the battery tested separately from the charging system? Also, what brand alternator was used?

I didn't get the battery tested seperately, but I could do that tonight. (No harm in doing it).

I replaced the Alternator with an AC Delco one, I believe (it was from Checker). As for if I am sure whether or not the prior alternator could have damaged the battery, no I am not sure... at this point I am not sure of anything.

Thanks

[xeroinfinity]

Not impossible that the new alternator was, or is damaged too.
I would think if the PCM was the culprit you would have other issues . just my

[Marty_Brownell]

Originally Posted by xeroinfinity

Not impossible that the new alternator was, or is damaged too.
I would think if the PCM was the culprit you would have other issues . just my

Thanks.

I think she might have other issues... well the car at least.. but I can't get it to run long enough to tell.

ha ha

[Marty_Brownell]

Battery was tested and came out okay.

I am pulling the PCM but since I do not have a manual I am not positive if this is it. Can someone verify if this is the PCM for me?

Thanks!

[BNaylor]

Did you pull that out of your Alero? Doesn't look like the PCM module to me. Looks like the body control module (BCM).

This how a PCM module looks. Should be located under the driver's side of the dash just left of the steering wheel. There should be 2 80 pin electrical connectors. Look specifically for the GM data labels that mentions SERV NO. XXXXXXXXX as shown in the pic.

[Marty_Brownell]

Thanks so much!!! Got it. Gotta love this forum.