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Headlight Illumination Issues

deputy

By deputy
in Troubleshooting & Recalls

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CounterMeasure Enthusiast

CounterMeasure

Posted
Posted

The bulb spec I read from Vosla included ratings for 13.2V. Keep in mind that in most vehicles, the 12v system is whatever the battery or alternator are providing, which means the bulbs in such vehicles can routinely see more than 12v. Like 20% more if the alternator is putting out 14v. The bulb spec also included data for 14v. I assume the BCM is providing some level of voltage regulation for the headlights, however I am not positive as I haven't tested it. I think its a safe assumption it is if they have to flash it. However I do know the 12v lighter plugs in the vehicle go through the BCM, but are not regulated to 12v. Testing showed they are whatever the alternator is putting out.

 

Easy enough for me to test....once it warms up.

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BIGDOGx Senior Enthusiast

BIGDOGx

Posted
Posted

Dealer got the bulbs on order, thanks to those who fed the info to keep us up to date on things regarding this tsb.

mafd2 Senior Enthusiast

mafd2

Posted
Posted

The BCM must regulate the voltage to the headlights. It's not like on older vehicles when you rev the engine and the lights would get brighter :lol: .

windward_coug Enthusiast

windward_coug

Posted
Posted

I got my truck back from the dealer and had a chance to test it out tonight. My first impressions are that its noticeably brighter, I could see the guesstimates of a 40% increase being accurate. I have a lot more peripheral light from the beam pattern as well which really helps in the rural area I live. The beam pattern also seems to extend a lot further ahead I'm actually hoping my low beams don't blind oncoming traffic as I feel they may be angled a little high.

jamin87ss Senior Enthusiast

jamin87ss

Posted
Posted

I got my truck back from the dealer and had a chance to test it out tonight. My first impressions are that its noticeably brighter, I could see the guesstimates of a 40% increase being accurate. I have a lot more peripheral light from the beam pattern as well which really helps in the rural area I live. The beam pattern also seems to extend a lot further ahead I'm actually hoping my low beams don't blind oncoming traffic as I feel they may be angled a little high.

Great news!!

Ranch55 Enthusiast

Ranch55

Posted
Posted

I got my truck back from the dealer and had a chance to test it out tonight. My first impressions are that its noticeably brighter, I could see the guesstimates of a 40% increase being accurate. I have a lot more peripheral light from the beam pattern as well which really helps in the rural area I live. The beam pattern also seems to extend a lot further ahead I'm actually hoping my low beams don't blind oncoming traffic as I feel they may be angled a little high.

 

A simple adjustment with your torx screw driver to adjust the vertical beam height. Easy to get to.

fastxr Enthusiast

fastxr

Posted
Posted

I got my truck back from the dealer and had a chance to test it out tonight. My first impressions are that its noticeably brighter, I could see the guesstimates of a 40% increase being accurate. I have a lot more peripheral light from the beam pattern as well which really helps in the rural area I live. The beam pattern also seems to extend a lot further ahead I'm actually hoping my low beams don't blind oncoming traffic as I feel they may be angled a little high.

That is interesting that you find the beams to be set a bit high as part of the service bulletin was to ensure the headlights are correctly aimed, may want to check with your service people on what they actually did.

2014Carbon Enthusiast

2014Carbon

Posted
Posted

Called GMC Customer Service and they directed me to a different local dealership. I spoke with the service manager who was very friendly, and stated they had performed a number of these TSBs already. She also mentioned they end up servicing a lot of vehicles bought from the dealership I bought mine due to issues with the service department. I'm scheduled for tomorrow, will report back after! Thank you guys for your diligence with this issue!

Skeeter McSkeet Senior Enthusiast

Skeeter McSkeet

Posted
Posted

Called my dealership this morning, they said they hadn't heard anything about this. The service guy said he was looking on the Gm site and didn't see anything listed for my vehicle. I told him it wasn't a recall it was a TSB and he said he couldn't find it. Any advice on how to proceed or someone I could tell him to contact regarding the update?

 

Thanks

 

 

-Skeet

B&J Aviation Enthusiast

B&J Aviation

Posted
Posted

Just got a copy of TSB PIT5374. Dealership could not find it until I told them it was not a recall. Had to clarify twice it was a TSB (assuming that is a technical service bulletin).

 

Not sure how else to post it except in .jpg. Dealership has ordered the bulbs.

 

PIT5374%20pg1_zpsbaryt1wr.jpg

PIT5374%20pg2_zpswajlopb9.jpg

PIT5374%20pg3_zpshlqvsvcp.jpg

PIT5374%20pg4_zps0qyy81lf.jpg

Skeeter McSkeet Senior Enthusiast

Skeeter McSkeet

Posted
Posted

Never mind here it is

Pit5374

I gave him the bulletin number a few times along with my vin, I'm guessing he was looking for a recall. It sounded like he was on something similar to the mygmc site as he was talking about my warranty info and service records like you would find on there.

 

I'm going to text the pics of the bulletin above to my cousin who's a salesman out there and have him go show the service department.

 

Edit* cousin is off today but he gave me the email for the service advisor. I sent him an email and attached the photos of the bulletin above. Thanks for posting those.

 

-Skeet

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