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Discussion Starter #1
Hello gentlemen,

Long time lurker here, I've got another problem a quick search here has not repaired. I have a Chevy Silverado 2005 LT, with the 5.3l, with 65k miles. Recently, past month, the voltage meter has been reading the bottom end (9v) which I assume is reading 0v, or it reads nornal, 14-15v, and sometimes reads high, 16v. I understand these have a computer controlled alternator which adjusts the voltage output depending on the power needs, but having the voltage drop to below 9v is odd.

No error codes as of yet.
 

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I'd run it down to AutoZone or some other place that does free charging system checks. It could be low voltage or alternator fault, or it could be the guage or the stepper motor for the guage.

**edit .. Good info below by Mike 99Heartbeat. It looks like you're covered if it's a stepper motor 100% parts & labor since you're under 75K & less than 7 years old.
 

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I would also recommend that you have this looked at. Please keep us posted. You can contact me via private message as well. Thank you in advance.

Tricia, GM Customer Service.
 

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I pretty sure your computer controls the voltage, there is no regulator. If you have a multimeter check the voltage at the battery on dc and see if it is reading the same as your gauge. Then you know if you have a problem with a gauge or the charging system. I would also check and see if gm recall on the cluster falls under your year, I think they warrenty it up to 75K. Unless your battery is older than five years old I would pay up two hours for a gm tech to troubleshot insted putting a $100 battery and $300 alternator on.
 

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If the Problem does turn-out to be the Gauge.....its most likely the Stepper Motor for the Alt Gauge is going out/bad......which is a Common Problem with the 03" to 05" Trucks/SUV's......G.M./Chevy has a a Special Coverage Adjustment.....it is for the 2003 to 2005" Trucks/SUV's Dash Cluster's......where the Gauges Stick.....Flutter and/or Become inoperative,

The Special Coverage Adjustment is the Following,
......If your vehicle is within 7 years or 70,000 miles (110,000 km) of the date it was first placed in service, GM must replace the instrument panel (parts and labor) for free.

......If your vehicle is between 70,001 miles (110,001 km) and 80,000 miles (130,000 km) of the date it was first placed in service, GM must replace the instrument panel (parts) for free. Any labor costs will be the responsibility of the vehicle owner.

......If your vehicle is older than 7 years or over 80,000 miles, you no longer qualify for the special coverage adjustment and must seek alternative means of repair.

Edit:.....Below is information, that goes into Detail Regarding the Special Coverage Adjustment from G.M./Chevy on the Dash Cluster's,

There has Never been an Official Recall from General Motors regarding widespread speedometer problems, but a 2007 Class Action Settlement qualifies certain owners for a (Special Coverage Adjustment).....(Policy Adjustment 07187a) to their standard warranty for allegedly defective speedometers.
Common symptoms include:


  • Speedometer displays incorrectly
  • Speedometer stops working
  • Tachometer needle sticks, jumps, or pegs
  • Fuel gauge flutters
  • Entire instrument panel fails
The common cause for all these issues is a faulty stepper motor (XC5.168). The motor was used throughout General Motor’s entire production line from 2003 to 2007. For those with a technical bent, this includes the GMT800, K20, GM360, and GMX380 platforms.
Models effected include (click link to determine qualifying status):

Don’t see your vehicle listed? Contact the experts in speedometer problems and repair for quick answers.



 

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I'd run it down to AutoZone or some other place that does free charging system checks. It could be low voltage or alternator fault, or it could be the guage or the stepper motor for the guage.

**edit .. Good info below by Mike 99Heartbeat. It looks like you're covered if it's a stepper motor 100% parts & labor since you're under 75K & less than 7 years old.
Stephan.....I missed that you had mentioned that the problem could be the stepper motor...........Sorry about that....:glasses:
 

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Discussion Starter #7
Thanks for the replies, I took my car to both Kragen and AZ and they tested the alternator on the car. Both places said that the battery is bad, I removed the battery and took it to AZ, they tested it and said it is at 100 percent, but the machine is listing it as bad. Could this be the source of the issue?

How can I test the stepper motor?

Thanks
 

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You know that sounds kind of like a bad chassis or body ground Def. Take them loose & check them. They should be clean & shiny, no rust or corrosion where they bolt to the frame & body. Also check your engine ground. That would explain why the battery checked bad in the truck, but passed on the bench test. If it turns out to be a stapper motor for your guage, don't even mess with it. It appears your truck is still covered under warranty. There's a thread here on GMTC about how to repl stepper motors but it's a pita.

Mike, I'm glad you put that warranty info in there cuz I had forgotten that GM was covering some of them & I never would have remembered what years or mileage ha ha :)
 

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Discussion Starter #9
Thanks for the new reply,

the battery failed the bench test, but listed 100 percent at the same time. 100 percent and bad battery, has me confused. I will check the grounds in the engine bay.
 

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Thanks for the new reply,

the battery failed the bench test, but listed 100 percent at the same time. 100 percent and bad battery, has me confused. I will check the grounds in the engine bay.
What? that has me confused too. What do they mean by 100%??? 100% failure?? Did they explain??
** Did they mean your charging system was 100% good & the battery was bad, or were they saying the battery was at 100% .. but still bad & needed replaced?
 

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when you turn the key to on, the meter has the battery( Vs) when you start the truck you get the alternator output.
9v is very odd
 

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Discussion Starter #12
Grounds checked out good. I discovered something new, though. When the car is shut off and key is out the voltage sits at 14-15, when started the voltage goes to maximum. With key on, voltage stays at 14-16.
 

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Discussion Starter #13
Took it to the dealer, they verified that the guage was faulty and are repairing it for free.

Thanks for all your help.
 

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Took it to the dealer, they verified that the guage was faulty and are repairing it for free.

Thanks for all your help.
I am glad to see that you are working with your dealer to have this concern resolved. If you have any further questions or concern please feel free to contact me directly. Thank you.

Tricia, GM Customer Service.
 
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