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2017 GMC Acadia SLE-2 3.6 V6
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Discussion Starter · #1 ·
Hello all. I bought a used 2017 GMC Acadia back in January. I was driving home tonight and I noticed that my driver side headlight seemed brighter than the passenger side. So when I got home I pulled up to the garage and sure enough the passenger side headlight will dim and brighten but the driver side headlight doesn’t change and is much brighter. I have factory halogen projectors. Any ideas what can cause this? Thanks in advance.
 

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What bulb does your headlight use? Halogen or? Also, is your Acadia the older body style or the newer +2017 shorter body style?
 

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It is a halogen bulb. My car is a 2017 new body style.
There is an internal shutter in the headlight that switches it to high beam mode. If you roll down your windows without the engine running. . . turn your headlights on and switch back and forth between low and high beam.
You should be able to hear the shutter mechanism. Sort of a quiet "thunk".

Try switching back and forth between HI and Low a few times and then check it. That may clear it, but is sounds like the internal shutter may be stuck.

Or. . . turn the headlights on and give it a good 'ol fashion wrap on the headlight from the back side under the hood. Otherwise. . . it may be defective and need a replacement.
 

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2017 GMC Acadia SLE-2 3.6 V6
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Discussion Starter · #5 ·
There is an internal shutter in the headlight that switches it to high beam mode. If you roll down your windows without the engine running. . . turn your headlights on and switch back and forth between low and high beam.
You should be able to hear the shutter mechanism. Sort of a quiet "thunk".

Try switching back and forth between HI and Low a few times and then check it. That may clear it, but is sounds like the internal shutter may be stuck.

Or. . . turn the headlights on and give it a good 'ol fashion wrap on the headlight from the back side under the hood. Otherwise. . . it may be defective and need a replacement.
There is an internal shutter in the headlight that switches it to high beam mode. If you roll down your windows without the engine running. . . turn your headlights on and switch back and forth between low and high beam.
You should be able to hear the shutter mechanism. Sort of a quiet "thunk".

Try switching back and forth between HI and Low a few times and then check it. That may clear it, but is sounds like the internal shutter may be stuck.

Or. . . turn the headlights on and give it a good 'ol fashion wrap on the headlight from the back side under the hood. Otherwise. . . it may be defective and need a replacement.
I guess the shutter is stuck. The passenger side works but the driver side changes just a tiny bit. So when I get home today I’ll look at it. I appreciate the info!
 

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Yes . . possibly the shutter actuator or wiring may be damaged or inoperative
 

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Does the shutter sit in front of the bulb? It’s not part of the actual bulb, right?
Yes , , the shutter is in front of the bulb and not part of the bulb.
You could also check connections to the headlight and assure there is no electrical corrosion or damage to the wiring.
 
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