I think these things have 2 adjuster screws per fixture. One adjusts horizontal, the other vertical.

 

You cannot adjust horizontal aiming left to right. Just the vertical aimpoint of both beams at a fixed distance.
If the aiming screw is not lifting or dropping the intensely lighted patch on the barn wall or garage door at night your headlamp assembly is damaged and will likely need to be replaced.
Improper left to right alignment is usually from body damage.
If the height between the Low and High beams is not the same comparing the left to the right lamp one or both of the lamps are screwed up. Some lamps have tamper covers over one or more alignment screws but these are really a last resort and many only have the unguarded vertical height adjustment.

This is the headlamp aiming page from my 8th gen W Body service manuals showing the aimpoint dot and the adjustment screw.

This is the writeup I did for this on my 2005 Silverado
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Brand new headlamps are not aimed properly. One of mine was setup for squirrel hunting in the trees.

The adjustment method in the video works very well.
I would recommend doing this after dark.

You need;

• Two inch wide blue painters tape
• Sharpie
• Yardstick to measure the headlamp aiming mark height and mark aimpoint height on the tape on the door
• Thirty foot measuring tape.
• 5 or 6 gal bucket filled with sand
• Four or five foot landscaping stake

You need a flat surface that's 90° to the ground and the ground needs to be level for at least 35ft back from it.
I put a landscaping stake in a bucket of sand at 25ft from the garage door I was using and backed the vehicle up til the corner of the front bumper was even with the stake.

 

Thank you so much! Looks like I'll be shopping for new headlights soon.

 

Which way do you turn the screw to adjust the lamp up (it is too low)?

 

@Ab24675678908u6

1995~2005 and 2006~2011
(and probably 2012~2020)

CLOCKWISE to RAISE CENTERLINE OF BEAM.

Notes:
1995~2005 adjust vertically and horizontally.

2006~2011 adjust vertically only.

My gathering is 2012~2020 adjust vertically only but I never looked into it.

Uninstall and reinstall are covered in owners manuals and service manuals. If you need an owners manual there is a reservoir of manuals here just search in this site (top of most screens) for your model year + owners manual example "2010 owner manual"

A depository of Owners Manuals:

https://www.impalaforums.com/threads/2000-to-2020-impala-owners-manuals-and-sales-brocures-in-pdf-format.1894265/

Headlamp Aiming is covered in service manuals for each model year group. Example Haynes manuals for Impala 1995~2005 and Haynes manual for Impala 2006~2011 show steps and sequences. I presume 2012+ manuals do too.

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