Headlights flickering

[Toddzaracki]

I have a 2008 Tahoe ltz with around 120,000 miles it and the headlights are flickering very bad at night. Low beams it’s very noticeable almost to the point it seems like they are going to go out. Volt gauge on dash does not move and no other lights flicker. I have checked and tried a different relay. Looking for insight on other things to check or if anyone has experienced this.

 

[swathdiver]

I have a 2008 Tahoe ltz with around 120,000 miles it and the headlights are flickering very bad at night. Low beams it’s very noticeable almost to the point it seems like they are going to go out. Volt gauge on dash does not move and no other lights flicker. I have checked and tried a different relay. Looking for insight on other things to check or if anyone has experienced this.

How old is your battery and have you checked its cables and the grounds lately? Are the lights stock?

Right off of the battery on the negative cable is a 3 or 4 pin connector, disconnect that and see if the lights stop flickering. That controls alternator output and charging. Unplugging it takes it back to old school charging at max power all the time. If you're not familiar with it, look up RVC, Regulated Voltage Control and EPM, Electronic Power Management.

 

[Toddzaracki]

Lights are stock and battery age is unknown. It was in the vehicle when we bought it 3 years ago. I will check the grounds, battery cables are tight and posts are clean. I will try unplugging that and see what happens . If that fixes it are we looking at a bad voltage regulator ?

 

[Jimmyy]

Start with a new battery. 3 years is about as long as they last.

 

[Toddzaracki]

Did finally get around to replacing the battery. Issue is better but headlights still flicker. Not as frequent as before but still noticeable.

 

[Geotrash]

Did finally get around to replacing the battery. Issue is better but headlights still flicker. Not as frequent as before but still noticeable.

The rectifier in the alternator is also a common source of this once they start to go. I have two of these - one in each Yukon and they're excellent:

https://a.co/d/gkZ4u0C

 

[B-train]

You beat me to it.....replace the alternator.

I was driving my new-to-me 2008 Deanli home from CA and had the light flicker all through NV at night. Pulled off and reseated the battery connections, alternator wires, etc. Some improvement, but still there. Voltage good @14v

Made it back to WI and retested - voltage ok. Figured ther rectifier was flaking out so I replaced with a new one.........smooth lights since. Just do yourself a favor and buy a NEW , not reman alternator.

 

[Toddzaracki]

Alright just ordered one. We will see how this goes !

 

[Dustin Jackson]

I am having a similar problem. Lights dim when coming to a stop or when RPM drop, crank has been sluggish recently, and my cigarette lighter is showing that when my Tahoe sit my battery only has 11.8v. My charging gauge still looks normally, varies between 12 and 15. and my battery, cables, belts, and pulleys are all under 1 year old so I don't want to start throwing parts at this thing until I am sure what the problem is. I took my Tahoe to Orileys and they tested both alternator and battery and they said both are good.

So without replacing both my battery and my alternator at the same time should I just wait until my Tahoe stops starting to start throwing parts at it?

 

[Charlie207]

My lights had been flickering. Replaced my alternator because the bearings were on their way out, and just replaced the battery because it was losing capacity.

Light flickering all gone.