07 denali headlight fluctuations.

[ny_summit]

I recently installed some aftermarket headlights with LED bulbs I purchased. I realized today when ever I pressed anything that uses electric the bulbs will get brighter for a second. For example closing a window.
Then when I shut the vehicle off the lights got much brighter and stayed brighter till they turned off. So basically the bulbs are brighter when I just turn the key vs the vehicle running.
Afew months I installed a new alternator so I don't believe that's the issue. Can it be the battery? Or anyone have a similar experience.

And now that I think about it I believe it did the same when I had the oem headlights and halogen bulbs. Thanks for the help!

 

[Joseph Garcia]

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

Have you checked the voltage in both instances to see if the voltage is noticeably different when the lights are dimmer and brighter?

 

[ny_summit]

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

Have you checked the voltage in both instances to see if the voltage is noticeably different when the lights are dimmer and brighter?

My car charger shows the voltage. It seems when voltage drops the led bulb is getting brighter which is weird. When the truck is running its at its usual 14ish volts. Once I shut it off its around 12.xx volts.
Also when hitting the window switches the volts drop for a second till the alternators adjust it. And in that moment of lower volts the bulb gets brighter.

 

[Doubeleive]

You might want to double check the wiring and grounds, maybe even just run them on a relay instead if they want more voltage, generally voltage dips are either poor ground or weak vehicle battery