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Headlight Illumination Issues

deputy

By deputy
in Troubleshooting & Recalls

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mafd2 Senior Enthusiast

mafd2

Posted
Posted

I've been combing this thread for a while now and I don't really see any silverado guys chiming in about this issue. Is this mainly a Sierra issue? Because higher trim silverados have projectors too. Is the problem just a crappy projector?

 

It sounds like GM's BCM voltage increase and higher lumen halogen bulb is a functional, yet very much duct-tape fix to what appears to be a systemic problem.

 

I would THINK.. that 2016 or 2017 they will revise the headlight to alleviate this issue.

 

My uncle is dead set on a new GMC so I'm trying to sort of get ahead of the curve on this issue for him as well, cos I know he's gonna say something.

I think they dropped the ball on the voltage. Most headlights on other vehicles have 14v going to them and not just 12. Remember on older vehicles when you would rev the engine from idle and the lights got brighter? That's because 14v were going to the lights which is what the alternator was putting out at higher rpm's. Now with computers and a BCM, whatever voltage is programmed in the BCM is what you will get at the headlights. If it was programmed for 12v it will remain at 12v no matter how high you rev the engine. Now with the new update, there's constantly 14v going to the headlights no matter what rpm.

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WLC Enthusiast

WLC

Posted
Posted

I think they dropped the ball on the voltage. Most headlights on other vehicles have 14v going to them and not just 12. Remember on older vehicles when you would rev the engine from idle and the lights got brighter? That's because 14v were going to the lights which is what the alternator was putting out at higher rpm's. Now with computers and a BCM, whatever voltage is programmed in the BCM is what you will get at the headlights. If it was programmed for 12v it will remain at 12v no matter how high you rev the engine. Now with the new update, there's constantly 14v going to the headlights no matter what rpm.

 

13.8 to14.2 was the range from my old mech days.Pull the battery cable and see if the engine still runs.Ahhhhhh.......Those were the days! Set the dwell @30 Change the plugs and adjust the carb. We have come a long ways. Some good some not so good!
ember1205 Senior Enthusiast

ember1205

Posted
Posted

Just got back from having the update done on mine. Verified that the Vosla bulbs were installed. I'm presuming that the BCM flash was done since some of the settings in IntelliLink were reset on me (irritating). Can't verify proper seating or aiming until I get a chance to drive at night.

 

Hopeful...

mafd2 Senior Enthusiast

mafd2

Posted
Posted

13.8 to14.2 was the range from my old mech days.Pull the battery cable and see if the engine still runs.Ahhhhhh.......Those were the days! Set the dwell @30 Change the plugs and adjust the carb. We have come a long ways. Some good some not so good!

Yep spot on! Dwell 28-32 :P

theatasigma Enthusiast

theatasigma

Posted
Posted

I've been combing this thread for a while now and I don't really see any silverado guys chiming in about this issue. Is this mainly a Sierra issue? Because higher trim silverados have projectors too. Is the problem just a crappy projector?

 

It sounds like GM's BCM voltage increase and higher lumen halogen bulb is a functional, yet very much duct-tape fix to what appears to be a systemic problem.

 

I would THINK.. that 2016 or 2017 they will revise the headlight to alleviate this issue.

 

My uncle is dead set on a new GMC so I'm trying to sort of get ahead of the curve on this issue for him as well, cos I know he's gonna say something.

 

Should be fine by then, the cut off date is late in 2014 for some Sierras and the rest in early 2015. Depends on where they were built.

MattUofM Enthusiast

MattUofM

Posted
Posted

So, the day before my last day at the gmc dealer, I had a good long discussion with the GM rep for the northwest. He's a cool guy, likes to get stuff done unlike his colleagues. Anyway, I told him what an oversight not putting HID's on a $50k truck was and that their competitors like ford have them already and that the new Titan will get them and ram is also getting them. He agreed with me. Then I told him about all our complaints and he said he hadn't seen this site before...needless to say, he is showing this sight to some of his bosses

ember1205 Senior Enthusiast

ember1205

Posted
Posted

Just got back from having the update done on mine. Verified that the Vosla bulbs were installed. I'm presuming that the BCM flash was done since some of the settings in IntelliLink were reset on me (irritating). Can't verify proper seating or aiming until I get a chance to drive at night.

 

Hopeful...

 

Got a chance to drive it at night last night.

 

The good: Brighter output, wider spread of light.

The bad: There are distinct "hot spots" in the light output. I can easily see about six different areas across the spread that are distinctly brighter than other areas. So, the wash isn't nice and smooth. There are some areas that are also slightly darker than others as well.

 

Can someone post up pictures of what to check to ensure that the bulbs are installed properly? What are the tabs to look at, and how does a properly installed one look compared to one that isn't properly installed?

 

I had to adjust the lights up slightly - I'm not entirely sure that they re-aimed them (since they had recently re-aimed them for me before the bulb swap).

TheElementalCashew Enthusiast

TheElementalCashew

Posted
Posted

I've been combing this thread for a while now and I don't really see any silverado guys chiming in about this issue. Is this mainly a Sierra issue? Because higher trim silverados have projectors too. Is the problem just a crappy projector?

 

It sounds like GM's BCM voltage increase and higher lumen halogen bulb is a functional, yet very much duct-tape fix to what appears to be a systemic problem.

 

I would THINK.. that 2016 or 2017 they will revise the headlight to alleviate this issue.

 

My uncle is dead set on a new GMC so I'm trying to sort of get ahead of the curve on this issue for him as well, cos I know he's gonna say something.

Yes, I had an LTZ with projectors as a loaner and the light output was terrible compared to my LT, which has standard headlights. I'm sure the projector isn't great quality to start, but they were just really dim and didn't spread light at the edges of the road. Similar problems to these GMC issues.

Tommyboyl New Member

Tommyboyl

Posted
Posted

My dealer was very helpful once I gave them the tsb # from this site thanks everyone!

My dealer was very helpful once I gave them the tsb # from this site thanks everyone!

POS VETT Enthusiast

POS VETT

Posted
Posted

 

Got a chance to drive it at night last night.

 

The good: Brighter output, wider spread of light.

The bad: There are distinct "hot spots" in the light output. I can easily see about six different areas across the spread that are distinctly brighter than other areas. So, the wash isn't nice and smooth. There are some areas that are also slightly darker than others as well.

 

Can someone post up pictures of what to check to ensure that the bulbs are installed properly? What are the tabs to look at, and how does a properly installed one look compared to one that isn't properly installed?

 

I had to adjust the lights up slightly - I'm not entirely sure that they re-aimed them (since they had recently re-aimed them for me before the bulb swap).

The bulbs are difficult to see when installed. I believe your bulbs are not seated correctly. The light pattern should not change before the changeover, the only difference is brightness level.

ember1205 Senior Enthusiast

ember1205

Posted
Posted

The bulbs are difficult to see when installed. I believe your bulbs are not seated correctly. The light pattern should not change before the changeover, the only difference is brightness level.

 

The pattern absolutely changes - the OEM bulb did not project anything to the shoulders to speak of, and cornering left the inside area (of the corner) essentially pitch black. The new lights disperse light to the sides better than the OEM bulbs and are also a fair amount brighter.

 

My issue is that the wash is not smooth - there are areas that are slightly brighter and slightly darker than others.

Spurshot Senior Enthusiast

Spurshot

Posted
Posted

13.8 to14.2 was the range from my old mech days.Pull the battery cable and see if the engine still runs.Ahhhhhh.......Those were the days! Set the dwell @30 Change the plugs and adjust the carb. We have come a long ways. Some good some not so good!

 

Yeah.....repeat every 10,000 miles. Don't forget to change the cap and rotor too. I remember having a big selection of distributor weights and springs and all those fishing hook boxes with carburetor jets. Jets for Quadra-jets, jets for Holley's, jets for Webers, power valves. ...now I just BBQ.

robwah New Member

robwah

Posted
Posted

Just got my headlights swapped and firmware updated. Huge improvement while driving at night

WLC Enthusiast

WLC

Posted
Posted

Yeah.....repeat every 10,000 miles. Don't forget to change the cap and rotor too. I remember having a big selection of distributor weights and springs and all those fishing hook boxes with carburetor jets. Jets for Quadra-jets, jets for Holley's, jets for Webers, power valves. ...now I just BBQ.

You know we are telling how old we are!

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