Why is my battery light staying on?

Tiny
KINGEARNEST
  • MEMBER
  • 2006 CHEVROLET TRAILBLAZER
  • 89,000 MILES
On my 06 trailblazer never have any starting troubles even when key is out it is slightly illuminated. Battery light stays lightly illuminated at all times. Started vehicle took off negative it didn't die. Shows good voltage in vehicle when running. Never has any sluggish starting problems. Someone says it could be key switch but when you take key out everything goes off like radio the windows wont roll down so key switch is fine. Someone says it is a battery heat sensor. Any ideas.
Thursday, March 22nd, 2012 AT 1:04 AM

20 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
First of all never remove the battery cable while its running or with the key on in a vehicle with a computer.You can damage the computer.Have you had the battery alternator tested?If not you need to do that first.Also have you made sure the battery cables are clean and tight.Do you have a multi meter to do some testing?

Read the guide below

https://www.2carpros.com/articles/how-to-check-a-car-alternator
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Thursday, March 22nd, 2012 AT 1:11 AM
Tiny
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  • 6 POSTS
Thanks for the fast response. No I havent had the alternator tested yet. Does it have to come off to be tested or can advanced auto test it while on the vehicle? Yeah I cleaned the post connecting to the battery. No I dont have a meter but I will buy one what do you recommend. Can the alternator cause that light to be on even though its charging. I remember the older cars as long as you could take the terminal off while running that would show you the alternator was charging. All help and suggestions will be greatly appreciated. Thanks David
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Thursday, March 22nd, 2012 AT 10:18 PM
Tiny
SATURNTECH9
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As far as a meter goes just get one that has a 20 volt dc setting and a ohms setting. You can have the alternator tested in the vechile which I would do also have the battery tested. Lets see how those two test and and go from there.
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Friday, March 23rd, 2012 AT 4:18 AM
Tiny
KINGEARNEST
  • MEMBER
  • 6 POSTS
All checked out good at advanced auto, battery and alternator. They had me to start vehicle rev it up and turn on ac and high bems everything was good. I am thinking about putting black tape over the light. Seems to have no effect on vehicle so any more suggestions.
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Friday, March 23rd, 2012 AT 10:26 PM
Tiny
SATURNTECH9
  • MECHANIC
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It says if its charging like its supposed to then use a scan tool and see if the voltage on the scan tool reads 10-15 volts if its does then replace the IPC. The instrument panel control module.
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Friday, March 23rd, 2012 AT 11:10 PM
Tiny
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  • 6 POSTS
Is the IPC something I can change or is it a dealer install. Can this be purchased at advanced or is it a dealer item. Thanks
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Saturday, March 24th, 2012 AT 12:12 AM
Tiny
SATURNTECH9
  • MECHANIC
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Most of the ipcs are part of the clusters and sometimes require programing from the dealer. I have most work though.
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Saturday, March 24th, 2012 AT 12:54 AM
Tiny
KINGEARNEST
  • MEMBER
  • 6 POSTS
Would you think the speedometer cluster is going bad. Drspeedometer shows they can fix it for $189 what do you suggest?
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Wednesday, March 28th, 2012 AT 1:24 AM
Tiny
SATURNTECH9
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Did you use a scantool to see what the ecm says its charging at?
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Wednesday, March 28th, 2012 AT 1:27 AM
Tiny
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  • 6 POSTS
Just replaced the speedometer cluster and the problem is solved the light is off. Real easy trade out watching the video on youtube will explain it all on the removal. Takes 20-30minutes to remove. You will need to go to dealer to get the milage corrected. Thanks for the help.
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Friday, April 27th, 2012 AT 11:39 PM
Tiny
SATURNTECH9
  • MECHANIC
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Your welcome glad to hear you got it fixed.
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Saturday, April 28th, 2012 AT 2:56 AM
Tiny
DAN2374
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 68,000 MILES
My battery light is dimmly lit when the vehicle is turned off. When engine is started light turns off and on. Voltage gauge read a little over 14 volts. I replace battery since it was 5 1/2 years old. Did not solve problem. I did disconnect the battery with engine running, engine quit after about 10 seconds.
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
HMAC300
  • MECHANIC
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First off, you shouldn't disconnect the battery with the engine running, computer controlled cars don't like that.have your alternator checked it may have a short in the diode bridge or voltage regulator. Also check all your body/engine / dash grounds.

Read the guide below, it will help

https://www.2carpros.com/articles/how-to-check-a-car-alternator
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
BARNELLOL
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 81,000 MILES
When I drive the light is dimmly lit and fades in and out. My battery gauge reads 14, which is right in the middle. When I shut the car off the battery light is still dimmly lit. What could be the issue? I am not experienceing any loss of power or anything else.
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Could be the powertrain control module controlled circuit of the field generation of the alternator
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
VAGOLDEN
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 60,000 MILES
My battery light is very faintly lit off and on. Even when car is turned off.
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
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You need to have your charging system inspected. Battery, alternator, terminals and cables all need to be tested and / or inspected. Most part stores will test batteries and alternators free of charge.
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
FDAIGNEAU
  • MEMBER
  • 2 POSTS
  • 2004 CHEVROLET TRAILBLAZER
  • 110,000 MILES
The alt light glows dim all the time. Key on eng. On, key off eng off does not matter. Alt and battery were replaced in last 3k miles. Charging system seems to be working fine. Any idea whats wrong and what to fix.
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Check all the connections. If they are ok, you have a bad diode in the alternator. Return to the shop and have it replaced under warranty

Roy
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)
Tiny
FDAIGNEAU
  • MEMBER
  • 2 POSTS
Thanks Roy I sure appreciate the help
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Tuesday, December 25th, 2018 AT 10:08 AM (Merged)

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