Headlights/Fog lights flicker?

tuckersnator · December 21, 2017

Hey all. 2015 Sierra SLE. I have searched a bit for this issue but haven't really found the same symptoms. I only notice it at night of course. When I am on the brakes, the headlights dim a bit. Then if the fog lights are on, it is even more noticeable. If I have the stock radio playing and there is a decent amount of base, I can see the headlights flicker to the tune, (fine if I was at a club). Also if I turn a blinker on, you can see the lights dim on and off. I saw some posts about G218 but they seemed more related to internal stuff. I only notice this in the exterior lights. Any ideas? I suspect maybe a weak ground connection somewhere? Thanks for any input.

hardcore2001 · January 1, 2018

Been having the same problem on my 2015 SLE also. I had the bulb update from gm @ 15000km with no problem that I noticed but 15000km later I had both bulbs blow days apart. Both blubs where replaced under warranty this is when I notice the headlight flicker took it back to GM and told them the problem they ended up replacing my alternator to no effect. The guy at the dealership told me that it is normal for this to happen (BULL). I'm running a small sub and amp 400w but this never happened before they replaced the lights.. From what I have read there is a BCM update that they do when they update the head lights so not too sure what happened between the last set of bulbs and these ones but I got a bad flicker. My guess that there is to much draw for the new light and the BCM that was never built to handle more wattage (that's my only a guess). Have you had the update done?? I plan to take it back to GM in the next week or so but will update with any other news.

P.S. If anyone from GM reads this Your headlights suck even with the update they have very little scatter light output and very boxy. Projection may be good for watching TV but not very good in watching the road. Would like to see GM drive with this setup at night in the rain and tell me its all good.

tuckersnator · January 2, 2018

I did get an update that increased the voltage, (supposedly). I think it made no difference. I will most likely take it in under warranty too. Just hate to if it is something that I can fix in the driveway like a loose wire. Battery cables seem fine.

hardcore2001 · January 2, 2018

Thanks we seem to be on the same page if you could keep me updated that would be great I will do the same. Good Luck

14Silverado14 · August 25, 2018

I have the same problem with my 2014 Silverado. I still have the original battery. I'm thinking I will start with a trip to the auto parts store for a load test and see what goes from there.

eatnupbyatornadr · September 6, 2018

2014 Silverado here as well with the same issue @ 105k miles. I do have a "newer" battery (40k miles on it give or take) + the Phillips crystalvision bulbs for at least four months.

I first started noticing the "flicker" in the head lights when I signal about two weeks ago. It's only a split second, but it's there. I also noticed my lights pulsating in cadance with the rpms at idle today, which I've never seen before (i was facing a reflective sign on a freeway exit and it gave me some visual feedback).

Perhaps the lights have always done this, and I never noticed with the stocks because they suck, but my wife's car and a few other guys at work have the same (or similar bulbs) with no noticeable flicker.

Ergo, I assume I have a problem lol

I'm going to take a trip to the auto store and see what they think. My voltage meter showed my alternator charging @ 14 and change I believe and my battery had 12 and change. This was a few weeks ago though when I got a DIC message of "low battery voltage". Perhaps something has changed since then...

tuckersnator · September 7, 2018

Hey all. I had this resolved. I know its been a while but I wanted to get a driving test in before replying and haven't really drove the truck at night all summer! Anyway, when I brought it in for maintenance they did a load test on the battery and pulled some codes from the truck, (I didn't have any error lights on). Apparently there were several codes for low voltage. Also the battery test came back as "flooded". They replaced the battery and all was well. Hope this helps.

eatnupbyatornadr · September 8, 2018

Interesting. I took mine to the auto shop and the battery passed plus the alternator. I didn't check for codes though.

14Silverado14 · October 22, 2018

Ok, so I have this problem now fixed. 1st I went to Auto Zone and they said my original battery was at 90%. I felt he had no idea what he was doing so I made an appt. with the dealership figuring it was low voltage issue somewhere in the wiring

They said the battery was going bad and showed me how they checked it with their equipment. So I bought a new battery. So far everything is ok.

I have all stock everything in my truck except for added on Hella fog lamps. I find it hard to believe a battery only lasts 4 years these days.

The battery you have to put in is for this model only so that the positive side of the terminal and other posts snap onto the top of the battery. I had to loosen the reserve antifreeze bottle to get the battery out. BTW The battery was over $200.00 so be forewarned. I never spent that much ever on a car battery !

tuckersnator · October 24, 2018

Yeah its crazy. I have another vehicle with a 7-8 year old Walmart battery that is still going strong. I can't believe GM is so cheap they went with an even cheaper battery than Walmart brand!

eatnupbyatornadr · November 15, 2018

I took a gamble & swapped the battery, eventhough the old one "passed" the tests at O'Reilly's. That was the problem apparently as my flickering/blinking headlight issue is no more.

tuckersnator · November 17, 2018

On 11/15/2018 at 6:54 AM, eatnupbyatornadr said:

I took a gamble & swapped the battery, eventhough the old one "passed" the tests at O'Reilly's. That was the problem apparently as my flickering/blinking headlight issue is no more.

Awesome! Hopefully others with the same issue will find this post.