2017 Yukon Denali Head Lights are terrible

[jpcortese]

My 2017 Denali was terrible when I picked it up. High beams were about as good as low beams should be. The lights were bright, but aimed way to low. Planned to adjust them up, but I added a 1.5" leveling kit the first week. Then they were just fine.

The headlights on my 2018 Denali are just plain awful and I will be going LED once I can decide which ones to go with. In the meantime I adjusted the beams higher yesterday to see if that helps.

 

[CMoore711]

The headlights on my 2018 Denali are just plain awful and I will be going LED once I can decide which ones to go with. In the meantime I adjusted the beams higher yesterday to see if that helps.

Let us know how it goes converting from HID to LED.

Is it doable? Sure I suppose. How far back in the headlight wiring system do you plan to replace? The factory lighting has an OSRAM D3S HID ballast in-line. There aren’t many LED bulb options in the D1S, D2S, or D3S size variant. This is because converting from HID to LED is not a conversion many people are interested in doing. Quick search shows there are some LED to HID “kits” available; some apparently just plug into an HID ballast while others somehow bypass the HID ballast? Or don’t use it? The thought of popping in an LED Bulb into a HID projector powered by an HID ballast or some sort of HID ballast LED Driver bypass “kit” just does not seem like a great solution nor a reliable one.

To be honest swapping from HID to LED in our GM trucks isn’t going to really solve your problem with light output either. The problem isn’t really the type of bulb, sure some can offer slight improvements, but the major issue is the GM bulb projector itself.

The pics below are not my vehicle, they were pulled from the GMfullsize.com forum. Although, this vehicle is a 2015 GMC Sierra, knowing GM, I’m confident that the type of projector is very similar to the ones in our Yukon’s. Sure there are probably some slight differences between the Yukon SLT Halogen projectors and the Denali HID projectors, but knowing GM I also wouldn’t be surprised if the only difference was the bulb socket. I only say this because of the clarity and still obvious projector cut-off Yukon SLT (and Tahoe owners with halogen projectors) are achieving by just swapping from factory halogen bulbs to LED or HID into their factory halogen projectors. The light pattern and cut-off typically remains the same just brighter. Definitely an improvement over stock, but only addresses part of the issue.

Let me show you what I mean... For all intensive purposes the pics from this 2015 GMC Sierra will show what I’m referring to.

Here is a photo comparison when the factory halogen bulbs in this 2015 GMC Sierra were upgraded to HID bulbs:



Sure the light is brighter, but look at the light output and beam pattern closely. See how there is a dark spot right in the middle of the light output and beam pattern and other random dark spots. Those same dark spots are there with the halogen bulb and the HID bulb. Swapping from an HID to an LED will be no different in your ‘18 Denali. Because the headlight projector and lens omitting the light output has remained the same.

Now this photo shows going from an HID bulb in the factory projector to the same style (35W 5000K) HID bulb into a Lexus RX350 projector retrofit:



Dramatically different isn’t it? No more dark spots, the light output is consistent and the same brightness is throughout the entire beam pattern. They’re both Morimoto 35W 5000K HID bulbs, the difference is the projector not the bulb.

Sure there is an upgrade in light output going from halogen to HID or LED. I don’t think swapping bulbs from HID to LED, and vice versa for that matter, in our GM factory projector headlights is going to make that much of a difference. You want to fix the light output change the projector and do a retrofit. Sure it’s a lot more involved and more expensive. But it’s clear from these images the weak point of our headlights is the GM factory projector in our headlights, regardless of what bulb you use.

 

[jpcortese]

Let us know how it goes converting from HID to LED.

Is it doable? Sure I suppose. How far back in the headlight wiring system do you plan to replace? The factory lighting has an OSRAM D3S HID ballast in-line. There aren’t many LED bulb options in the D1S, D2S, or D3S size variant. This is because converting from HID to LED is not a conversion many people are interested in doing. Quick search shows there are some LED to HID “kits” available; some apparently just plug into an HID ballast while others somehow bypass the HID ballast? Or don’t use it? The thought of popping in an LED Bulb into a HID projector powered by an HID ballast or some sort of HID ballast LED Driver bypass “kit” just does not seem like a great solution nor a reliable one.

To be honest swapping from HID to LED in our GM trucks isn’t going to really solve your problem with light output either. The problem isn’t really the type of bulb, sure some can offer slight improvements, but the major issue is the GM bulb projector itself.

The pics below are not my vehicle, they were pulled from the GMfullsize.com forum. Although, this vehicle is a 2015 GMC Sierra, knowing GM, I’m confident that the type of projector is very similar to the ones in our Yukon’s. Sure there are probably some slight differences between the Yukon SLT Halogen projectors and the Denali HID projectors, but knowing GM I also wouldn’t be surprised if the only difference was the bulb socket. I only say this because of the clarity and still obvious projector cut-off Yukon SLT (and Tahoe owners with halogen projectors) are achieving by just swapping from factory halogen bulbs to LED or HID into their factory halogen projectors. The light pattern and cut-off typically remains the same just brighter. Definitely an improvement over stock, but only addresses part of the issue.

Let me show you what I mean... For all intensive purposes the pics from this 2015 GMC Sierra will show what I’m referring to.

Here is a photo comparison when the factory halogen bulbs in this 2015 GMC Sierra were upgraded to HID bulbs:

View attachment 234737

Sure the light is brighter, but look at the light output and beam pattern closely. See how there is a dark spot right in the middle of the light output and beam pattern and other random dark spots. Those same dark spots are there with the halogen bulb and the HID bulb. Swapping from an HID to an LED will be no different in your ‘18 Denali. Because the headlight projector and lens omitting the light output has remained the same.

Now this photo shows going from an HID bulb in the factory projector to the same style (35W 5000K) HID bulb into a Lexus RX350 projector retrofit:

View attachment 234738

Dramatically different isn’t it? No more dark spots, the light output is consistent and the same brightness is throughout the entire beam pattern. They’re both Morimoto 35W 5000K HID bulbs, the difference is the projector not the bulb.

Sure there is an upgrade in light output going from halogen to HID or LED. I don’t think swapping bulbs from HID to LED, and vice versa for that matter, in our GM factory projector headlights is going to make that much of a difference. You want to fix the light output change the projector and do a retrofit. Sure it’s a lot more involved and more expensive. But it’s clear from these images the weak point of our headlights is the GM factory projector in our headlights, regardless of what bulb you use.

WOW, thanks for the explanation. It was very well thought out and described. I'll have to think about whether it makes any sense doing a projector retrofit.

 

[cmatt]

To add some additional info, here’s the factory halogen projector out of a Tahoe.







Here’s a factory HID projector out of an Impala. It’s the same as what’s in the Tahoe/Yukon minus the bi-xenon parts. Compared to the suv halogen projector, the lens (fresnel type) and projector bowl/mounting boss are different.








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[cmatt]

I’m working up the courage to retrofit these bi-xenon projectors with an STi clear lens in my Yukon.


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[Tiki]

I’ve read more about headlights in the last two days then I ever cared to. I’d agree in part that at least when it comes to projectors, it is more complicated. LEDs seem to be better halogen replacements in reflector headlights while projectors can be a mixed bag. It’s a bummer to hear that stock GM projectors are lack luster!

Above is DD SL1s LEDs in a factory Suburban housing. They look good but not amazing. DD from my reading seams to be one of the only companies that measures luxe across the full beam pattern in order to meet SAE/DOT regulations which at least gives me hope (includes measurements that would account for approved levels of glare). I may pick these up and if they don’t show an improvement try them in my Sierra reflector headlights.

@cmatt do the stock projectors units bolt into the headlight?

 

[cmatt]

View attachment 234786

I’ve read more about headlights in the last two days then I ever cared to. I’d agree in part that at least when it comes to projectors, it is more complicated. LEDs seem to be better halogen replacements in reflector headlights while projectors can be a mixed bag. It’s a bummer to hear that stock GM projectors are lack luster!

Above is DD SL1s LEDs in a factory Suburban housing. They look good but not amazing. DD from my reading seams to be one of the only companies that measures luxe across the full beam pattern in order to meet SAE/DOT regulations which at least gives me hope (includes measurements that would account for approved levels of glare). I may pick these up and if they don’t show an improvement try them in my Sierra reflector headlights.

@cmatt do the stock projectors units bolt into the headlight?

Yes, in the suvs. The front and back halves of the projector fasten to the internal reflector. That assembly then mounts to the rear headlight casing via ball joints. The low/high beam assembly is adjusted as one unit.






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[jpcortese]

Instead of doing a total projector replacement so I could go LED, I'm thinking that it might be easier to just replace what I have with a better bulb. Hopefully with some improvement from factory. I believe I have halogen bulbs (2018 Yukon Denali) but don't know exactly what I have and can find no reference to it in the owners manual. Can someone tell me? Are there better and stronger halogen bulbs that would be a direct replacement, and if so, what are they?

 

[Tiki]

Yes, in the suvs. The front and back halves of the projector fasten to the internal reflector. That assembly then mounts to the rear headlight casing via ball joints. The low/high beam assembly is adjusted as one unit.






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Looks fairly obvious but you have to open the whole assembly up to pull the projector don’t you?

 

[cmatt]

Looks fairly obvious but you have to open the whole assembly up to pull the projector don’t you?

Unfortunately, yes.


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