Alternator

[Topher90]

Hi I have a 2015 GMC Sierra, My alternator went out about a week ago so I changed it out. A couple days later the one they sold me went out also so I went and got another one. This has happened 2 more times. Is there odds that I have bad luck and have gotten bad alternators because they are rebuilt or could something be causing it to go bad? I have looked up and seen the computer could cause a failed alternator but nothing else is wrong with the truck. No engine light, no bad idle, nothing else just my voltage meter dropping and when I get the alternator tested they tell me it has a bad regulator. 

[Snowcamo]

I'd look into the Battery and ground connections. How old is the battery? Has it ever been dead?

[Topher90]

I replaced it 3 months before the alternator went out. I checked the battery already.

[BlancoSilverado]

What brand of alternator? I would also check the grounds and power cables. 

[Topher90]

It’s a duralast from autozone. I checked my grounds and stuff already. I know they tend to sell bad alternators just wasn’t sure if 4 was normal.

[rlcole321]

Those "Life Time" warrantees aren't any good for most electronics, mainly the ones you get from Auto Zone or Advanced. The PCM/VCM controls the Alt output to not "Overcharge" the battery, the cheap reg. they use may not have the capability to receive the proper control parameters. My suggestion is stick with AC Delco or Delphi, I know they cost more, but now you know why!!.......:)

[Topher90]

Thanks 

[Bill R.]

I have a 2018 Silverado with the same issue.  I bought a new OEM alternator through Rock auto and after a week of use have the same issue.  Oddly enough at night running lights and a/c it seems to work fine.