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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I put in a 140 amp alternator in my 2000 silverado 2500 6.0.

Customer Question

I put in a 140 amp alternator in my 2000 silverado 2500 6.0. My gauge is moving rapidly back and forth between 14 and 18 volts. The volts at the battery connections is at 14 volts and doesn't fluxuate with engine running. When the engine is off the battery volts are 12. What is my problem.
Submitted: 3 months ago.
Category: Chevy
Customer: replied 3 months ago.
how can I fix it?
Expert:  Joshua Davenport replied 3 months ago.

Good evening. First thing is to check and see if the voltage is fluctuating the same as the gauge says it is. This is done by connecting a multimeter to the battery and watching the voltage. If the voltage is fluctuating at the battery as well then it may be a problem with the alternator itself. If the voltage is steady then the gauge may be going bad. This is usually repaired by having the Instrument Cluster Repaired.

Customer: replied 3 months ago.
It's not fluctuating at the battery. So I need to pull out the instrument cluster and can I just get a new volt gauge or what would I do for repair?
Expert:  Joshua Davenport replied 3 months ago.

Yes that is correct. The cluster can be repaired. Parts can be found online to repair it yourself or many electronics repair businesses offer repair services as well.

Customer: replied 3 months ago.
Thank you for your help. I will try it myself.
Expert:  Joshua Davenport replied 3 months ago.

No problem at all. I'm glad I could help. GM clusters are fairly simple to repair.

Customer: replied 3 months ago.
I noticed this morning that my dash lights and headlights flicker alittle. Is there something I can do. My alternator only reads from 13.96 to 14.14
Expert:  Joshua Davenport replied 3 months ago.

The alternator voltage is in the range it should be. You can try "loading" the alternator by turning the blower and A/C on high and turning the high beam headlights on. If the flicker becomes worse than you have a current problem from the alternator. If the flicker doesn't change than there is a probably a problem with in the cluster.

Customer: replied 3 months ago.
At idle when loaded the gauge was stable. When I gave it rpms the gauge flickered.
Expert:  Joshua Davenport replied 2 months ago.

I apologize for the delay in responding. If the gauge is flickering as the rpm changes than it would seem to be a problem with the alternator itself. It should have steady current regardless of high rpms.