All lights are flickering and voltage is bouncing around

[Esko07]

Hey all! I recently replaced my battery and my alternator and now my voltage gauge is bouncing around and all lights (headlights and interior lights) are flickering while driving and while at idle. I replaced my battery and alternator as my battery recently died and it was overdue so I figured I might as well replace both since my rig has 71,000 miles on it. It is a 2009 GMC Yukon XL Denali.

I have been researching about RVC I think it is? From what I have found there is no voltage regulator outside of the alternator on this model. Is that accurate?

Visually it looks like my grounds are good but I have not yet tried to disconnect and clean any connections.

Is there something else I should be looking at?

 

[OR VietVet]

So.....you replaced battery because it died and battery was old and before this, you did not have flickering lights....correct? You also replaced the alternator because seemed like a good idea and now you have flickering lights. What brand of alternator? I would bet there is a diode problem in that alternator but I am just guessing. From what you have said and assuming you didn't mess up somewhere and leave a wire loose or unhooked, it points to a faulty new to you alternator. Is the belt tight and rolling smoothly?

 

[Doubeleive]

no logical reason to replace the alternator at 70k unless it died a short life, making noise, etc the average life of one can be more than twice that or more

 

[Geotrash]

Hey all! I recently replaced my battery and my alternator and now my voltage gauge is bouncing around and all lights (headlights and interior lights) are flickering while driving and while at idle. I replaced my battery and alternator as my battery recently died and it was overdue so I figured I might as well replace both since my rig has 71,000 miles on it. It is a 2009 GMC Yukon XL Denali.

I have been researching about RVC I think it is? From what I have found there is no voltage regulator outside of the alternator on this model. Is that accurate?

Visually it looks like my grounds are good but I have not yet tried to disconnect and clean any connections.

Is there something else I should be looking at?

I'd you bought a reman alternator, that's not uncommon behavior. But with only 71K on it, I'd put the original right back on. Lots of guys here have over 200K on their originals.