Battery Light

coloRADo_S10 · 12-29-2008, 05:37 PM

Hey guys. My mom has a 2001 4dr blazer and she said her battery light came on randomly while she was driving. Does that mean the battery is dead? about to die? Alternator?

Anybody have a clue?

PimpingA1997Jimmy · 12-29-2008, 06:00 PM

I dont know about the battery lites on our truck but i know when the battery light woould come on in my other car was when the alternator was dieing or the belt would be slipping so maybe the belt might be slipping just a guess im not sure but i hope this helps

coloRADo_S10 · 12-29-2008, 06:02 PM

Anything helps. Cuz the terminals are clean the batt is fairly new
(couple months) and the wires are fine.

cpolaris502 · 12-29-2008, 07:59 PM

I think it usually means that the alternator is starting to go or is gone. Like it is not recieving a charge, like when you have your key turned back and just the radio on i think the light comes on then.

Do you have any idea if the voltage meter dropped down while it was on?

Shawn-GMC · 12-29-2008, 08:50 PM

alternator is going, happened to me on my truck and i replaced the batt and it just died few days later.

weezin355 · 12-30-2008, 12:16 AM

The light will illuminate if the PCM detects a voltage less than 12volts or greater than 16volts.

coloRADo_S10 · 12-30-2008, 12:29 AM

Thats what i figured! Thanks guys. I really appreciate it. You guys all rock!

D.T. · 12-30-2008, 06:41 AM

I thought the light comes on if there is a voltage difference between the alternator output and the battery. If one is weak or low, the light illuminates. This is probably old school thinking though..

Check the voltmeter. I'd say it's the alternator also. Usually when I have one fail, it's the bearings, not the regulator/rectifier. They start to squeal or it just locks up and burns a belt. If the battery is going bad, it just doesn't want to turn over.

MikeInCtown · 12-30-2008, 07:57 AM

Quote: Originally Posted by D.T.

I thought the light comes on if there is a voltage difference between the alternator output and the battery. If one is weak or low, the light illuminates. This is probably old school thinking though..

Check the voltmeter. I'd say it's the alternator also. Usually when I have one fail, it's the bearings, not the regulator/rectifier. They start to squeal or it just locks up and burns a belt. If the battery is going bad, it just doesn't want to turn over.

I'd have to say the first part is probably true. In my 96 I had an alternator go bad. It was putting out some voltage, but not enough to charge the battery and less than it took to run the vehicle. As I was on the road, you could see the guage slowly move from what I would guess to be about 13v slowly down to just above the red line. Pulled over, changed the alt and there was barely enough juice to crank the truck over (2 seconds at most) Voltage slowly increased and charged the battery. The light NEVER came on.

coloRADo_S10 · 12-30-2008, 11:50 AM

For an alternator to work/ do its job it needs to be putting out atleast 14v. I took out my handy dandy voltmeter and its running at 11.78v and thats not enough!At that voltage it will not recharge the battery.

I NEED A NEW ALTERNATOR!

So ill be calling around looking for the best prices. so far checker is the cheapest at 115 lifetime warranty. So do some more looking and ill buy one and put it in tonight!

PimpingA1997Jimmy · 12-30-2008, 06:31 PM

I had a bat alternator it would not charge at idle but it would charge when the gas was going if you gave it gaas it would jump righ tup to above 14 but if it was just idling it would go down to like 11.5
but my light never came on from that problem

coloRADo_S10 · 12-31-2008, 03:34 AM

new alt in and light is off. problem solved!!!!!!!!!!!!

PimpingA1997Jimmy · 12-31-2008, 11:02 AM

glad to hear it

12-29-2008, 05:37 PM	#1
coloRADo_S10 Registered Boozer Age: 24 Join Date: Dec 2007 Posts: 1,306 Location: User is: OffLine	Battery Light Hey guys. My mom has a 2001 4dr blazer and she said her battery light came on randomly while she was driving. Does that mean the battery is dead? about to die? Alternator? Anybody have a clue?
	[Reply w/Quote]

12-29-2008, 06:00 PM	#2
PimpingA1997Jimmy Registered User Age: 30 Join Date: Jun 2008 Posts: 783 Location: User is: OffLine	Re: Battery Light I dont know about the battery lites on our truck but i know when the battery light woould come on in my other car was when the alternator was dieing or the belt would be slipping so maybe the belt might be slipping just a guess im not sure but i hope this helps
	[Reply w/Quote]

12-29-2008, 06:02 PM	#3
coloRADo_S10 Registered Boozer Age: 24 Join Date: Dec 2007 Posts: 1,306 Location: User is: OffLine	Re: Battery Light Anything helps. Cuz the terminals are clean the batt is fairly new (couple months) and the wires are fine.
	[Reply w/Quote]

12-29-2008, 07:59 PM	#4
cpolaris502 SmartTrak FTW Age: 21 Join Date: Jul 2005 Posts: 16,616 Location: Rogers, MN User is: OffLine	Re: Battery Light I think it usually means that the alternator is starting to go or is gone. Like it is not recieving a charge, like when you have your key turned back and just the radio on i think the light comes on then. Do you have any idea if the voltage meter dropped down while it was on?
	[Reply w/Quote]

12-29-2008, 08:50 PM	#5
Shawn-GMC Registered User Age: 19 Join Date: Jul 2006 Posts: 471 Location: Canada User is: OffLine	Re: Battery Light alternator is going, happened to me on my truck and i replaced the batt and it just died few days later.
	[Reply w/Quote]

12-30-2008, 12:16 AM	#6
weezin355 Registered User Age: 35 Join Date: May 2008 Posts: 70 Location: User is: OffLine	Re: Battery Light The light will illuminate if the PCM detects a voltage less than 12volts or greater than 16volts.
	[Reply w/Quote]

12-30-2008, 12:29 AM	#7
coloRADo_S10 Registered Boozer Age: 24 Join Date: Dec 2007 Posts: 1,306 Location: User is: OffLine	Re: Battery Light Thats what i figured! Thanks guys. I really appreciate it. You guys all rock!
	[Reply w/Quote]

12-30-2008, 06:41 AM	#8
D.T. Captain DIY Age: 42 Join Date: Dec 2008 Posts: 124 Location: Moneyapolis, MN User is: OffLine	Re: Battery Light I thought the light comes on if there is a voltage difference between the alternator output and the battery. If one is weak or low, the light illuminates. This is probably old school thinking though.. Check the voltmeter. I'd say it's the alternator also. Usually when I have one fail, it's the bearings, not the regulator/rectifier. They start to squeal or it just locks up and burns a belt. If the battery is going bad, it just doesn't want to turn over. Last edited by D.T. : 12-30-2008 at 06:42 AM.
	[Reply w/Quote]

12-30-2008, 07:57 AM	#9
MikeInCtown Registered User Age: 35 Join Date: Feb 2008 Posts: 927 Location: User is: OffLine	Re: Battery Light Quote: Originally Posted by D.T. I thought the light comes on if there is a voltage difference between the alternator output and the battery. If one is weak or low, the light illuminates. This is probably old school thinking though.. Check the voltmeter. I'd say it's the alternator also. Usually when I have one fail, it's the bearings, not the regulator/rectifier. They start to squeal or it just locks up and burns a belt. If the battery is going bad, it just doesn't want to turn over. I'd have to say the first part is probably true. In my 96 I had an alternator go bad. It was putting out some voltage, but not enough to charge the battery and less than it took to run the vehicle. As I was on the road, you could see the guage slowly move from what I would guess to be about 13v slowly down to just above the red line. Pulled over, changed the alt and there was barely enough juice to crank the truck over (2 seconds at most) Voltage slowly increased and charged the battery. The light NEVER came on.
	[Reply w/Quote]

12-30-2008, 11:50 AM	#10
coloRADo_S10 Registered Boozer Age: 24 Join Date: Dec 2007 Posts: 1,306 Location: User is: OffLine	Re: Battery Light For an alternator to work/ do its job it needs to be putting out atleast 14v. I took out my handy dandy voltmeter and its running at 11.78v and thats not enough!At that voltage it will not recharge the battery. I NEED A NEW ALTERNATOR! So ill be calling around looking for the best prices. so far checker is the cheapest at 115 lifetime warranty. So do some more looking and ill buy one and put it in tonight!
	[Reply w/Quote]

12-30-2008, 06:31 PM	#11
PimpingA1997Jimmy Registered User Age: 30 Join Date: Jun 2008 Posts: 783 Location: User is: OffLine	Re: Battery Light I had a bat alternator it would not charge at idle but it would charge when the gas was going if you gave it gaas it would jump righ tup to above 14 but if it was just idling it would go down to like 11.5 but my light never came on from that problem
	[Reply w/Quote]

12-31-2008, 03:34 AM	#12
coloRADo_S10 Registered Boozer Age: 24 Join Date: Dec 2007 Posts: 1,306 Location: User is: OffLine	Re: Battery Light new alt in and light is off. problem solved!!!!!!!!!!!!
	[Reply w/Quote]

12-31-2008, 11:02 AM	#13
PimpingA1997Jimmy Registered User Age: 30 Join Date: Jun 2008 Posts: 783 Location: User is: OffLine	Re: Battery Light glad to hear it
	[Reply w/Quote]