Weird Flickering lights

[Atrevino0497]

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

 

[Atrevino0497]

I’d like to add also when my lights are done going dim and bright I can’t replicate it even shutting off the vehicle and trying again. It almost seems to me that it stops when it gets warmed up and it’s done

 

[swathdiver]

Could be the negative battery cable is internally corroded and needs replacing. Many will say to check and clean your grounds. You said that you already tightened the terminals on top of the battery.

Usually when we see this, the battery is just about ready to give up the ghost. Don't know where you live but 4 years in the south is old.

 

[Atrevino0497]

Could be the negative battery cable is internally corroded and needs replacing. Many will say to check and clean your grounds. You said that you already tightened the terminals on top of the battery.

Usually when we see this, the battery is just about ready to give up the ghost. Don't know where you live but 4 years in the south is old.

I live in Minnesota, it’s strange that it only happens for the first 10 minutes randomly couple times in months

 

[Geotrash]

I live in Minnesota, it’s strange that it only happens for the first 10 minutes randomly couple times in months

It’s also during that time that the alternator is working the hardest to top up the battery, so any additional drain may be more than it can sustain. At 132k your alternator could be getting weak though I’ve seen them go over 200k on these.

I run these on my rigs and they’ve been great.

https://a.co/d/aAZfQDV

 

[iamdub]

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

Temperature is often a major factor in electrical, particularly in low voltage, high amp circuits. It mostly affects smaller circuits- "smaller" also referring to lower ampacity "weaker" ones. So, a poor battery, ground, positive cable connection can be more affected by temperature swings and they often are intermittent. As was mentioned, the alternator is first trying to recharge the battery from the biggest hit it takes- cranking the engine. So it's doing its maximum work while being quickly warmed up by both the engine and by the production of current. A weak/failing connection anywhere within the production, rectifying or regulation circuitry can cause power fluctuations. An aged battery is also likely to show its faults during these quick temperature and load swings. It really is a harsh environment when you think about what all is going on.

As for the gauge, its not gonna respond quickly enough to coincide with your very short-term fluctuations. I bet that if you had a digital gauge, such as those that plug into a power port ("cigarette lighter"), you'd see the numbers fluctuate.

The dimming cycles could even be associated with the A/C cycling off and on. Which, further reinforces that your charging system is in need of attention- Alternator and/or battery and/or the associated cable connections. After confirming all cable connections were good, I'd suspect the battery.

 

[Atrevino0497]

Temperature is often a major factor in electrical, particularly in low voltage, high amp circuits. It mostly affects smaller circuits- "smaller" also referring to lower ampacity "weaker" ones. So, a poor battery, ground, positive cable connection can be more affected by temperature swings and they often are intermittent. As was mentioned, the alternator is first trying to recharge the battery from the biggest hit it takes- cranking the engine. So it's doing its maximum work while being quickly warmed up by both the engine and by the production of current. A weak/failing connection anywhere within the production, rectifying or regulation circuitry can cause power fluctuations. An aged battery is also likely to show its faults during these quick temperature and load swings. It really is a harsh environment when you think about what all is going on.

As for the gauge, its not gonna respond quickly enough to coincide with your very short-term fluctuations. I bet that if you had a digital gauge, such as those that plug into a power port ("cigarette lighter"), you'd see the numbers fluctuate.

The dimming cycles could even be associated with the A/C cycling off and on. Which, further reinforces that your charging system is in need of attention- Alternator and/or battery and/or the associated cable connections. After confirming all cable connections were good, I'd suspect the battery.

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

 

[Atrevino0497]

Temperature is often a major factor in electrical, particularly in low voltage, high amp circuits. It mostly affects smaller circuits- "smaller" also referring to lower ampacity "weaker" ones. So, a poor battery, ground, positive cable connection can be more affected by temperature swings and they often are intermittent. As was mentioned, the alternator is first trying to recharge the battery from the biggest hit it takes- cranking the engine. So it's doing its maximum work while being quickly warmed up by both the engine and by the production of current. A weak/failing connection anywhere within the production, rectifying or regulation circuitry can cause power fluctuations. An aged battery is also likely to show its faults during these quick temperature and load swings. It really is a harsh environment when you think about what all is going on.

As for the gauge, its not gonna respond quickly enough to coincide with your very short-term fluctuations. I bet that if you had a digital gauge, such as those that plug into a power port ("cigarette lighter"), you'd see the numbers fluctuate.

The dimming cycles could even be associated with the A/C cycling off and on. Which, further reinforces that your charging system is in need of attention- Alternator and/or battery and/or the associated cable connections. After confirming all cable connections were good, I'd suspect the battery.

Temperature is often a major factor in electrical, particularly in low voltage, high amp circuits. It mostly affects smaller circuits- "smaller" also referring to lower ampacity "weaker" ones. So, a poor battery, ground, positive cable connection can be more affected by temperature swings and they often are intermittent. As was mentioned, the alternator is first trying to recharge the battery from the biggest hit it takes- cranking the engine. So it's doing its maximum work while being quickly warmed up by both the engine and by the production of current. A weak/failing connection anywhere within the production, rectifying or regulation circuitry can cause power fluctuations. An aged battery is also likely to show its faults during these quick temperature and load swings. It really is a harsh environment when you think about what all is going on.

As for the gauge, its not gonna respond quickly enough to coincide with your very short-term fluctuations. I bet that if you had a digital gauge, such as those that plug into a power port ("cigarette lighter"), you'd see the numbers fluctuate.

The dimming cycles could even be associated with the A/C cycling off and on. Which, further reinforces that your charging system is in need of attention- Alternator and/or battery and/or the associated cable connections. After confirming all cable connections were good, I'd suspect the battery.

Thankyou It’s been sitting over night now I’m going to check the surface charge on the battery and I’ll try load testing it with my multimeter. It’s funny that you said air conditioner because I made sure it was off last night as it was only 60 degrees out.

Even with the ac running I don’t have the dimming lights issue. I’m thinking the alternator is ready to give up and it would be a perfect time to replace the battery as well since I’m maintaining the charging system.

I just did a complete tune up this weekend with all the fluids, plugs and wires. Air filter serpentine belt etc. but on a positive note the alternators in these seems pretty straight forward in these 5.3’s

 

[Atrevino0497]

Temperature is often a major factor in electrical, particularly in low voltage, high amp circuits. It mostly affects smaller circuits- "smaller" also referring to lower ampacity "weaker" ones. So, a poor battery, ground, positive cable connection can be more affected by temperature swings and they often are intermittent. As was mentioned, the alternator is first trying to recharge the battery from the biggest hit it takes- cranking the engine. So it's doing its maximum work while being quickly warmed up by both the engine and by the production of current. A weak/failing connection anywhere within the production, rectifying or regulation circuitry can cause power fluctuations. An aged battery is also likely to show its faults during these quick temperature and load swings. It really is a harsh environment when you think about what all is going on.

As for the gauge, its not gonna respond quickly enough to coincide with your very short-term fluctuations. I bet that if you had a digital gauge, such as those that plug into a power port ("cigarette lighter"), you'd see the numbers fluctuate.

The dimming cycles could even be associated with the A/C cycling off and on. Which, further reinforces that your charging system is in need of attention- Alternator and/or battery and/or the associated cable connections. After confirming all cable connections were good, I'd suspect the battery.

I’ve went back out to check a few things I checked the surface charge on battery and it read 12.18v I turned it on and it was bouncing from 14.34 & 14.54v running.

I also did check the belt and make sure it had good tension and it does but I loosened the belt and spun the alternator and notice there’s a chirping and when it runs comes to think of it there is a intermittent Whirring sound

 

[Geotrash]

I’ve went back out to check a few things I checked the surface charge on battery and it read 12.18v I turned it on and it was bouncing from 14.34 & 14.54v running.

I also did check the belt and make sure it had good tension and it does but I loosened the belt and spun the alternator and notice there’s a chirping and when it runs comes to think of it there is a intermittent Whirring sound

You found your culprit. That battery is toast. But if the alternator spins freely with no play or grittiness in the bearings, then you probably have some more time on that and can budget for replacing it at a later date.

 

[Atrevino0497]

You found your culprit. That battery is toast. But if the alternator spins freely with no play or grittiness in the bearings, then you probably have some more time on that and can budget for replacing it at a later date.

Correct, hopefully this fixes the slight issue with the dimming. I actually just picked up a new battery right before you replied, now with the alternator part. Would the whirring I’m hearing be it under load for trying to keep up with the battery? And what about the chirp when I spun the alternator by hand? Would it be worth adding a little lubrication ?

 

[Geotrash]

Correct, hopefully this fixes the slight issue with the dimming. I actually just picked up a new battery right before you replied, now with the alternator part. Would the whirring I’m hearing be it under load for trying to keep up with the battery? And what about the chirp when I spun the alternator by hand? Would it be worth adding a little lubrication ?

The whirring could be the chirping just played faster I would not try to lubricate the alternator bearings. They're sealed and the excess lube that flings off could have other consequences. But if you don't mind spending the extra money now, then replacing the alternator is not a bad idea as a preventative measure anyway. One less thing to worry about on your next road trip.

 

[Atrevino0497]

The whirring could be the chirping just played faster I would not try to lubricate the alternator bearings. They're sealed and the excess lube that flings off could have other consequences. But if you don't mind spending the extra money now, then replacing the alternator is not a bad idea as a preventative measure anyway. One less thing to worry about on your next road trip.

I’ll see how the new battery pans out first , I just dished out about $2500 on getting everything up to my standards lol. this past weekend I was wrenching all day doing plugs wires , o2 sensors, belt. Brakes and rotors air filter and now battery. She just came back from an alignment and new tires too.

It’s sad how people treat these trucks and yet they’re really forgiving. I’ll update later on as the next couple weeks play out and see if I notice an improvement or not.

On a positive note the only other thing I can think of causing this would be the alternator since I took all grounds off and cleaned them up with a wire brush and all the terminals are looking great. I even went ahead and checked all the terminals for the fuse box underneath.

But if it’s not 1 thing it’s always another, going to stay positive though because I really enjoy working on my vehicles and taking care of them feels amazing

 

[Atrevino0497]

It’s also during that time that the alternator is working the hardest to top up the battery, so any additional drain may be more than it can sustain. At 132k your alternator could be getting weak though I’ve seen them go over 200k on these.

I run these on my rigs and they’ve been great.

https://a.co/d/aAZfQDV

I really appreciate your help and everyone else’s, it’s always the simplest things we forget to double check. I replaced the battery and double checked every terminal I could find under the hood branching from the wiring harness.

 

[Atrevino0497]

You found your culprit. That battery is toast. But if the alternator spins freely with no play or grittiness in the bearings, then you probably have some more time on that and can budget for replacing it at a later date.

You found your culprit. That battery is toast. But if the alternator spins freely with no play or grittiness in the bearings, then you probably have some more time on that and can budget for replacing it at a later date.

You found your culprit. That battery is toast. But if the alternator spins freely with no play or grittiness in the bearings, then you probably have some more time on that

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

 

[Geotrash]

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

You have time on your side. The link I pasted above is a 160 amp unit. Chinese made but I've found them to be both durable and flawless in operation. But you can buy an AC Delco from Rock Auto for $242.

More Information for GM GENUINE 25877026

 

[iamdub]

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

I'm not one to throw darts, but with your symptoms and a 4+ year-old battery, that'd be my first reaction. Not saying it is 100% your problem, but the battery is aged and you finding it having 12.18V at rest is at least identifying a future problem.

 

[iamdub]

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

If you're feelin it, you can get an alternator from a '19+ truck with the KW5 option, which is a 220A alternator. It's an OEM high-output alternator that can be had from $90-$150, from low-mileage (wrecked truck take-offs) or brand new. Myself and another member, @mikez71 recently converted to this alternator. He directly bolted his on. I... didn't.

Search part numbers 13534128, 13527173, 13531751 and 13536552.

 

[Atrevino0497]

I'm not one to throw darts, but with your symptoms and a 4+ year-old battery, that'd be my first reaction. Not saying it is 100% your problem, but the battery is aged and you finding it having 12.18V at rest is at least identifying a future problem.

I 100% agree with you no doubt, so far everything seems good. But I’m still keeping an eye on it for a few weeks to see if it will do it again. There was no pattern to the dimming and it only happened once on 2 separate occasions, 2weeks from each other( must be a Monday thing ). I only can notice it at night for the first 5-10 minutes when my headlights are on.

I am firmly leaning towards that battery. Since it only does it for a short period of time and then disappears. Usually with an alternator there’s more pronounced symptoms that are consistent and those aren’t strongly present enough to lead me believing that it is the alternator. But with 132k miles now it wouldn’t hurt changing out the alternator as a precaution and stuff the old one in the back for a rainy day

 

[Atrevino0497]

If you're feelin it, you can get an alternator from a '19+ truck with the KW1 option, which is a 220A alternator. It's an OEM high-output alternator that can be had from $90-$150, from low-mileage (wrecked truck take-offs) or brand new. Myself and another member, @mikez71 recently converted to this alternator. He directly bolted his on. I... didn't.

Search part numbers 13534128, 13527173, 13531751 and 13536552.

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