DRL headlight turning blue

2021 Sierra X31 · June 6, 2022

2 hours ago, f8l vnm said:

My 19 was fixed a few months back and so far so good.

One of our 2020 Sierras in our farm has the blue light as well. No big deal for a work truck but we will have it looked at at oil change time. I wish i knew what was causing this , small issue i guess

Do you have a copy of the service ticket on your ‘19? I’d like to know what they did to fix. GM already replaced the entire headlight unit on mine and it turned purple a week later. I haven’t been able to find anyone on any forum that has actually stated anything replaced that actually fixed the problem.

OliverDennis52 · June 7, 2022

22 hours ago, 2021 Sierra X31 said:

Do you have a copy of the service ticket on your ‘19? I’d like to know what they did to fix. GM already replaced the entire headlight unit on mine and it turned purple a week later. I haven’t been able to find anyone on any forum that has actually stated anything replaced that actually fixed the problem.

Had mine done last year, replaced the unit and all good so far.

2021 Sierra X31 · June 7, 2022

45 minutes ago, OliverDennis52 said:

Had mine done last year, replaced the unit and all good so far.

Hmmm... so sounds like the headlight unit they replaced mine with was also defective. Maybe they finally fixed the issue in production. Guess I’ll get mine swapped again.

kj3475 · July 9, 2022

Went to my dealer earlier in the week for this. Driver side blue on drl only, headlights on- it returns to normal.

First of all, the service advisor douche wouldn't even acknowledge that he saw a difference in the light color.

After several demonstrations of changing from headlights on to auto... he said he'd have the tech look at it. STILL wouldn't acknowledge the color change.

Go to pick up truck today... he tries convincing me that it's the angle that I'm looking at it as it's "a downward angle". He also says it's on both lights. It's only the angle ! LMFAO.

On the way out I got the service advisors name from a sales guy walking by. I asked him.. he do you see any difference in my drls ? He said, hmm... the drivers side looks a little different on the top. I thanked him and left.

Time to find a new dealer after a call to the service manager to express my extreme displeasure.

2021 Sierra X31 · August 10, 2022

Well I was driving home the other day and saw my trucks reflection and noticed that my passenger side DRL finally has failed and turned purple also. So now both my lights match at least

mwlewis558 · August 10, 2022

I work in lighting (not automotive) but I can tell you that the reason for the color shift in the LED's is the degradation of the phosphorus over the LED chip. An LED emits royal blue light and they use phosphorus to shift the color to white. When it begins to degrade it shifts the color to a blueish/purple.

kj3475 · August 10, 2022

1 hour ago, mwlewis558 said:

I work in lighting (not automotive) but I can tell you that the reason for the color shift in the LED's is the degradation of the phosphorus over the LED chip. An LED emits royal blue light and they use phosphorus to shift the color to white. When it begins to degrade it shifts the color to a blueish/purple.

Then why is it that is is only when lights are in "auto" mode?

When you switch to parking only or headlight on, the drl turns back to the proper white color.

I have a tech that believes the problem lies some where in between the sensor that picks up the sunlight on the dash and the top drl.

Edited August 10, 2022 by kj3475
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