Weird Flickering lights

[B-train]

So would you recommend changing the battery and alternator out? All of the cables look great, I just got done doing a complete tune up on her this weekend. All new fluid, plugs and wires , air filter , serpentine belt, etc. upon belt replacement I also checked all of my pulleys and they appeared fine as well but I know that doesn’t mean an alternator is on its way out

Had the same issue 2008 Denali, 142k. Lights flickered ever so slightly. All connections clean and tight, battery new. New replacement 160 watt alternator from carquest solved the issue. You might have a bad rectifier or brushes that make better contact once things expand with heat.

If the battery tests good, throw an alternator in it. Easy 20 min job

 

[iamdub]

Interesting . I’ll take a look. Thankyou very much any advice is greatly appreciated

I mistyped. The RPO to look for is KW5. I'll edit my post. It's a direct replacement, 20-minute job. But it had some small points I chose to modify, making it a two-hour job. Regardless, I highly recommend it. Great bang for the buck upgrade with an OEM part.

 

[Atrevino0497]

I mistyped. The RPO to look for is KW5. I'll edit my post. It's a direct replacement, 20-minute job. But it had some small points I chose to modify, making it a two-hour job. Regardless, I highly recommend it. Great bang for the buck upgrade with an OEM part.

I’ll have to check it all out , so far everything is working out pretty well. I get off work in a half hour, every night I just hope it doesn’t go back. I’m fairly confident that the new battery will solve

 

[iamdub]

I’ll have to check it all out , so far everything is working out pretty well. I get off work in a half hour, every night I just hope it doesn’t go back. I’m fairly confident that the new battery will solve

If not and the alternator actually is the culprit, it wouldn't be a waste cuz you would be needing a battery sooner than later, anyway.


I was curious so I looked it up:

Maybe since we've been buying them up, all the cheaper ones have been sold. Here's one with only 13K miles for $165. But, brand new for $175 here. Brand new with minor, superficial damage for $145 here.

 

[BG1988]

I was pricing them out, I have RPO KW1 requiring the 160 amp instead of the 145amp I believe. I found a duralast gold for $259.99, Delco for $404.99 or Bosch for $304.99.

Part of me wants to stick with Ac delco

just have the alternator rebuilt. i did that on my Toyota Corolla it was only 120-220$(depending on how far you want it rebuilt) to rebuild it (bad diode) most likely one of the diode(s) have gone flaky....

a remanufactured was 450$

 

[Atrevino0497]

Update… my voltmeter on the instrument cluster is slowly moving from 12.80 to 13.50 volts. Am I going to be going alternator shopping? When I start my vehicle it’ll go above 14 and after driving around it’ll slowly go back and fourth

 

[ZKWBQD]

2013 Tahoe LTZ 5.3 with 132k miles, I just purchased this rig in December of 2022.

A couple weeks ago I was getting in my truck to go home from work at 11:30pm so it was dark, for the first 10 minutes of my drive I noticed all of my lights going dim and normal and would repeat this about every 5-10 seconds and stopped out of the blue as if it needed to warm up first . Nothing could replicate it while voltage meter on dash showed stable and no performance issues at all!

A couple weeks goes by until today same thing happened, I got home checked all my grounds, they were all shiny and snug and I checked the positive cable on the battery also. This only happened twice now in the 8k miles since I’ve owned this vehicle. Alternator appears original

I will say I do notice sometimes the headlights and interior lights flicker very little if I’m paying attention while idiling . This happened out of the blue and while this is happening the volt meter doesn’t even flinch and stays steady above 14v. Battery is interstate made in 2019 by the way. Any insights are appreciated

One thing to be aware of, MANY people make modifications (in software, or hardware) in order to disable the Daytime Running Lights, or otherwise have full control of the lights. (Don't do this in Canada, they're required there.) In newer, GM vehicles, the Daytime Running Lights, are dedicated, so problems with the main headlights should not occur. However, in older GM products they would dim the main headlights to serve as the DRLs. This made disabling the DRLs more complicated. Most GM vehicles sold to government agencies, have the Daytime Running Lights disabled. They do this through software, not hardware modifications. I am not saying this is your problem, but do consider it as a possibility. On current GM vehicles, the Daytime Running Lights can be completely disabled on every engine start. So technically, General Motors Can no longer be accused of having "Forced Lighting".

 

[Atrevino0497]

I replaced the alternator this morning , and in the midst of putting my engine cover back on I broke the white hvac heater hose t valve. So while I was at it I went ahead and replaced the black one also since they’re known for going bad and topped off coolant. However I started her up and the voltage immediately when back up to 14.75v and is holding steady not moving around. So I think that was the issue.

I had gotten an ultima one because that’s what I was able to get my hand on at the moment. But it does have a lifetime warranty and it’s very easy to put in.

I ended up saving my old one just for emergency in case this one dies on me on the side of the road , I know the old one will at least be able to get me back home

 

[iamdub]

View attachment 400597View attachment 400598
Update… my voltmeter on the instrument cluster is slowly moving from 12.80 to 13.50 volts. Am I going to be going alternator shopping? When I start my vehicle it’ll go above 14 and after driving around it’ll slowly go back and fourth

With RVC, we can't say for certain. You can disable RVC by unplugging the sensor on the ground cable connected to the battery. Personally, I prefer to have it, so I'd say to do this only as a test.

 

[k9rockydog]

2013 Tahoe LTZ 5.3 with 132k miles, I just purchased this rig in December of 2022.

A couple weeks ago I was getting in my truck to go home from work at 11:30pm so it was dark, for the first 10 minutes of my drive I noticed all of my lights going dim and normal and would repeat this about every 5-10 seconds and stopped out of the blue as if it needed to warm up first . Nothing could replicate it while voltage meter on dash showed stable and no performance issues at all!

A couple weeks goes by until today same thing happened, I got home checked all my grounds, they were all shiny and snug and I checked the positive cable on the battery also. This only happened twice now in the 8k miles since I’ve owned this vehicle. Alternator appears original

I will say I do notice sometimes the headlights and interior lights flicker very little if I’m paying attention while idiling . This happened out of the blue and while this is happening the volt meter doesn’t even flinch and stays steady above 14v. Battery is interstate made in 2019 by the way. Any insights are appreciated

I guess because I have not posted enough.. I dont have post ability, merely comment ability.. either way.. I had same issue.. checked all connections etc.. I just went and got a new 160A which is what was in mine..
flicker gone, runs quieter, right low-beam works again.. headlights are TWICE as bright..
battery was new.. connections were good.. DONE

 

[Atrevino0497]

I guess because I have not posted enough.. I dont have post ability, merely comment ability.. either way.. I had same issue.. checked all connections etc.. I just went and got a new 160A which is what was in mine..
flicker gone, runs quieter, right low-beam works again.. headlights are TWICE as bright..
battery was new.. connections were good.. DONE

That’s exactly what I did even though it’s been months. I went ahead and did the battery anyways as well because it was getting up there in age. No more issues