[06Z71~T]

Started with increasing voltage so checked and was told needed a new alternator. Replaced it and the issue has gotten increasingly worse. It not only red lines but is maxed out. When this started and i turned off the vehicle the voltage guage would stay at roughly 12 now it goes from½ inch passed 19 back down to 19. Has anyone had similar issues? 2006 tahoe z71

Thanks in advance

 

[dogbiscuit]

you have another bad alternator. The voltage regulator is internal and is the ONLY thing that controls the charging voltage. Even the vehicles with the computer controlled systems can not be commanded to overcharge ,they just turn the alternator off to save fuel

 

[jglew82]

Did you test the actual output voltage with a meter to rule out faulty gauge?

 

[Rocket Man]

Th

Did you test the actual output voltage with a meter to rule out faulty gauge?

This ^^^^. Stepper motors in the NBS gauges are known to fail, causing them to read extremely inaccurate. Use a good DVM to read voltage at the battery.