• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

All the lights lightly flicker when idling

joeblackavalanche

Full Member
Joined
May 15, 2021
Messages
110
2012 chevy avalanche......lights flicker, be it the dome or headlights......put a new battery and alternator which helped a little......checked the ground off the engine to the fire wall and the ground off the battery to the front of the frame, i cleaned them up.......i know this is a loaded question but are there any other ground locations? .....i didnt check directly off the negative cable at the battery though as of yet, but just wanted to know if anyone else knew of some hidden grounds that would make this problem happen......no codes on the dash .....wish it was an easy fix as the headlights drive me crazy as they pulsate against the garage door at night......i put di-electric grease on the frame ground and i got a dash engine light so i cleaned it off and the dash light went away and the headlights were also dimmer when i had the grease on the ground......im assuming its all a ground issue making the lights pulsate.......im no electrician and dont really understand electricity........any suggestions would be greatly appreciated
 
2012 chevy avalanche......lights flicker, be it the dome or headlights......put a new battery and alternator which helped a little......checked the ground off the engine to the fire wall and the ground off the battery to the front of the frame, i cleaned them up.......i know this is a loaded question but are there any other ground locations? .....i didnt check directly off the negative cable at the battery though as of yet, but just wanted to know if anyone else knew of some hidden grounds that would make this problem happen......no codes on the dash .....wish it was an easy fix as the headlights drive me crazy as they pulsate against the garage door at night......i put di-electric grease on the frame ground and i got a dash engine light so i cleaned it off and the dash light went away and the headlights were also dimmer when i had the grease on the ground......im assuming its all a ground issue making the lights pulsate.......im no electrician and dont really understand electricity........any suggestions would be greatly appreciated
Mine did this until I replaced the ground cable from the battery to the engine and to the frame, it also has a sensor on the cable that let's the alternator know of a voltage drop and kicks in the alternator to start charging, my tail lights even did it, there are grounds on the driver side on the frame and one on the frame under the driver's door and another in-between the 2 driver's side doors on the frame to the body. Hope this helps 🙏
 
Mine did this until I replaced the ground cable from the battery to the engine and to the frame, it also has a sensor on the cable that let's the alternator know of a voltage drop and kicks in the alternator to start charging, my tail lights even did it, there are grounds on the driver side on the frame and one on the frame under the driver's door and another in-between the 2 driver's side doors on the frame to the body. Hope this helps 🙏
it does help thank you......my cable from the negative battery goes to the front passenger side frame behind the bumper which i have to take off the wheel well to get to it......when i took it apart which is a blind situation it had two cables connected to the stud.....i assume the other is the cable that goes to the engine block like you were talking about, i couldnt really follow it......but this spring i will be investigating more with your info.......such a pain.......would be nice to have a lift......lol
 
it does help thank you......my cable from the negative battery goes to the front passenger side frame behind the bumper which i have to take off the wheel well to get to it......when i took it apart which is a blind situation it had two cables connected to the stud.....i assume the other is the cable that goes to the engine block like you were talking about, i couldnt really follow it......but this spring i will be investigating more with your info.......such a pain.......would be nice to have a lift......lol
The other wire on the frame is the headlight ground, it is in combination with the small battery ground and the bigger cable goes to the front of the engine block, making sure you have a good ground from the engine to the body and body to the frame. I added all kinds of grounds to my Avy, I got tired of trying to track down the bad grounds. Lol, good luck 👍
 
There's also grounding points front of truck I believe frame area behind drivers side fog lamp near radiator.
A ground point rear frame of truck between gas fill & Rear bumper.
Drivers door area frame grounding.
From oil fill at block corner the ecu ground connected.
I added grounding straps & ran ecu to block/body/and frame just to be sure ground stays good. Also put x2 extra ground straps from engine/transmission to frame & body meatal.
Helped get rid of ecu communications problems with sensors.
I believe I have a vacuum leak in evap or something causing my rich bank 1&2.
 
Well idle fluctuations slowing to stops & traction control warning lights come on then shut off quickly?
I shut off traction control & driving around with tc button off symptoms better.
Starting to think I've gotta get rear wheel speed sensors checked out, front hubs/drives/and steering arms new recently installed.so front speed sensors are brand new should be ok.
Any other suggestions to check on traction control system could be helpful
 
I watched a mechanic video who said our avalanches get corrosion inside the wire sheathing on ground cable mostly but he suggested replacing both?
I thought my negative cable might have problems but used multimeter ohms reading from block& frame to negative post, it tested good even with movement on thick negative cable. Low almost no resistance.
Had a question about the lighting flickering is it just the overhead dome lighting or do you see dash lights and headlights doing the flickering aswell?
I did replace my controller left steering wheel, it can turn on dome lights and dim/brighten dash lighting.
Mine was lil glow backlight burned out to see controls nights otherwise was good part.
I'm curious if that controller is causing the flickering.
If headlights flickering same time probably not the control box I'm thinking of.
 

Attachments

  • 16776002025586862485483917016135.jpg
    16776002025586862485483917016135.jpg
    140.8 KB · Views: 1
@joeblackavalanche
The battery also acts as a giant capacitor in the electrical system, evening out any voltage irregularities to an extent.
I'm thinking you might possibly have a defective battery (yeah I see that you replaced it) or there is some kind of connection issue between the battery and the truck's electrical system. A poorly grounded alternator can also cause strange problems. Time to bust out the multimeter and perform some voltage drop tests. Hopefully that will isolate where the trouble is.
 
I watched a mechanic video who said our avalanches get corrosion inside the wire sheathing on ground cable mostly but he suggested replacing both?
I thought my negative cable might have problems but used multimeter ohms reading from block& frame to negative post, it tested good even with movement on thick negative cable. Low almost no resistance.
Had a question about the lighting flickering is it just the overhead dome lighting or do you see dash lights and headlights doing the flickering aswell?
I did replace my controller left steering wheel, it can turn on dome lights and dim/brighten dash lighting.
Mine was lil glow backlight burned out to see controls nights otherwise was good part.
I'm curious if that controller is causing the flickering.
If headlights flickering same time probably not the control box I'm thinking of.
yeah the headlights flicker or pulsate .......
 
@joeblackavalanche
The battery also acts as a giant capacitor in the electrical system, evening out any voltage irregularities to an extent.
I'm thinking you might possibly have a defective battery (yeah I see that you replaced it) or there is some kind of connection issue between the battery and the truck's electrical system. A poorly grounded alternator can also cause strange problems. Time to bust out the multimeter and perform some voltage drop tests. Hopefully that will isolate where the trouble is.
unfortunately i have no electrical understanding........i watch videos and read books on electrical systems and it just doesnt click in my head how it works.......one video explained how and why a relay is needed and works and that helped me in understanding what it does and why it is needed but i seem i cant grasp the whole electrical concept.......i understand the basics of electricity but add a switch and i can understand that and the pathway of electrons but add anything else to the equation and im lost.......so using a multimeter is out of my realm and it pisses me off i just cant grasp its use......i make guitars and to this day after wiring them up for over 45 years i still screw it up if i try to wire them without a schematic in front of me.......my whole world would open up if i could grasp the whole concept......i had a learning disability in school.......but i am a very talented making things with my hands be it with metal or wood otherwise.......thanks for the suggestion and help........i didnt check the negative cable at the battery, maybe its got some loose connections being there is more than one wire coming off of it
 
with the battery connected i stupidly cleaned 2 grounds i could find and only one of them started arcing while pulling it apart and putting it back together after cleaning, that was the one connected to the top of the engine to the firewall by a braided strap.......the one from the battery terminal to the frame didnt arc while messing with it......maybe thats a problem
 
with the battery connected i stupidly cleaned 2 grounds i could find and only one of them started arcing while pulling it apart and putting it back together after cleaning, that was the one connected to the top of the engine to the firewall by a braided strap.......the one from the battery terminal to the frame didnt arc while messing with it......maybe thats a problem
I'm assuming that your engine block-to-battery negative ground is good as it is starting and running ok.
There should be a frame-to-body ground as well. It could very well be rotted away and completely absent, as that tends to happen to those braided ground straps being exposed to moisture and road salt for any length of time. If you can't find it, just make a body-to-frame ground at two cleaned off points. The arcing you state that is happening with the one ground strap you cleaned up could indicate that the body is not grounded well enough. The body has various grounding points...so one of them could be loose or corroded. There's a ton of info about these body grounds on here. One of which is located under the truck in the vicinity of the driver's door jamb if I remember right. Please let us know what you find! 👍
 
I'm assuming that your engine block-to-battery negative ground is good as it is starting and running ok.
There should be a frame-to-body ground as well. It could very well be rotted away and completely absent, as that tends to happen to those braided ground straps being exposed to moisture and road salt for any length of time. If you can't find it, just make a body-to-frame ground at two cleaned off points. The arcing you state that is happening with the one ground strap you cleaned up could indicate that the body is not grounded well enough. The body has various grounding points...so one of them could be loose or corroded. There's a ton of info about these body grounds on here. One of which is located under the truck in the vicinity of the driver's door jamb if I remember right. Please let us know what you find! 👍
ok ill be more detailed once the good weather starts and i can crawl underneath the truck in the driveway.......we are having a major storm this weekend in maine so im hunkering down for a few.......yeah the truck is running great except for the sketchy transmission and pulsating lights.......im wondering if the bad ground is making the transmission act wonky?
 
I'm assuming that your engine block-to-battery negative ground is good as it is starting and running ok.
There should be a frame-to-body ground as well. It could very well be rotted away and completely absent, as that tends to happen to those braided ground straps being exposed to moisture and road salt for any length of time. If you can't find it, just make a body-to-frame ground at two cleaned off points. The arcing you state that is happening with the one ground strap you cleaned up could indicate that the body is not grounded well enough. The body has various grounding points...so one of them could be loose or corroded. There's a ton of info about these body grounds on here. One of which is located under the truck in the vicinity of the driver's door jamb if I remember right. Please let us know what you find! 👍
so if i add a new ground of my own like you say i wont do any harm? ......can you have too many grounds
 
no you cannot have too many grounds only hurts your wallet.
 
this is what i noticed last night having to go to the store before the storm......when i unlocked the truck the headlights come on and they were shining into a snow bank in the yard and when i started the truck they are not as bright.......so i assume im not getting the full strength of light from a bad ground somewhere?
 
off topic but i did an observation......im new to this truck ownership........the 2012 i own knocks like crazy........i checked the oil and i had just changed it a few months ago and it was down 4 quarts.....i assume that is the afm causing this oil consumption? and another thing i mentioned how it shifts lousy and has a little shudder and bad gas mileage averaging 15.1 mpg per what the dash is saying.......so topping off the oil got the knocking to a minimum and i added about 5 oz of shudder fix to the transmission but this time the premium grade of the product which cost twice as much and that brought the transmission to come alive and now the truck shifts better and acts like a kind of new truck and going up hills is not a struggle anymore and where i would burn an 1/8 of a tank just going to the post office which is about 4 miles away the gas gauge didnt even move and when i go to wally world i usually burn a 1/4 of a tank and again the gas gauge needle moved just a hair.......im afraid to read what the dash says at what i am getting for gas mileage but in my heart of hearts it looks good gas gauge wise and im happy with that.....maybe one day ill hit the button and see what im really getting for mpg's.......lol.......truck isnt perfect and it just rolled over 180K yesterday but its gets better in some areas and it might be for a short time or temporary but it is an improvement and thats a good thing and fixes were on the cheap.......so far we have 8 inches of snow today and still have 4 hours left for it to end........then its going to be sunny and in the 40's for the remainder of the week
 
Down 4 quarts in a few months is a big problem and points to more than just the AFM. I mean, the engine takes 6qts with a filter change, so you lost two thirds of your oil in a few months - not good. Do you have any significant leaks?

I'd be happy averaging 15mpg in my Avy. I'm lucky if I get 14...
 
Down 4 quarts in a few months is a big problem and points to more than just the AFM. I mean, the engine takes 6qts with a filter change, so you lost two thirds of your oil in a few months - not good. Do you have any significant leaks?

I'd be happy averaging 15mpg in my Avy. I'm lucky if I get 14...
i did notice 2 spots in the snow when i moved the truck, they were about a foot apart and inline with the drivers side passenger door.......the spots were green......other than that no other signs of leaks on the snow
 
Most of that is good news! That's great the shudder fix worked so well.

Sounds like you might be in MI. My daughter is in Ypsilanti with 7-8 inches and 220K homes without power.
we got about a foot of heavy snow.......and its stopped around 4pm today........will snowblow when im good and ready.......lol
 
Back
Top