Aiming headlights


Original poster
Jan 26, 2022
New York
Good morning,

I'm going to be aiming my headlights since I got a replacement set of housings. I noticed on the plastic trim cover over the radiator, near where the headlight adjustment screws are, there is a marking with a picture of the headlights and 1.25% molded into the plastic.

Everything I've seen has said that there should be a 2" drop from the center of the headlight lens compared to the actual bean hotspot output on the cross section on the wall. Does this mean on the Trailblazer that the drop should be 1.25% of that 2" instead? Its a 2002 LTZ.

Any input would be ideal. Thank you.

Picture pasted below for clarity.



Dec 3, 2011
Brighton, CO
As a starting point, I would park your truck in front of a wall, using your old headlights, and mark the wall hotspot with a bit of tape. Then put the new set in, and align to that mark. That will be a good starting point.

I cant help beyond that, this is how I aim during replacement.


Master Blaster
Dec 4, 2011
Ottawa, ON
Search for a video on YouTube by ChrisFix for aiming headlights. He has a very good one that I use the method on my vehicles.


Active Member
Dec 5, 2011
Central Pennsylvania
That's the recommended percentage angle. If I have my math right that works out to around 3/4 of a degree of downslope. Which is 2" down at 13.5 feet. This honestly doesn't sound right, but the calculators I used gave these numbers.

I usually use 2 - 4" down at 20 feet (ish). Then test drive. I've adjusted up from there more than down.

Also, keep in mind that where your headlights point has as much to do with the load in the car as it does where they're adjusted to. Put two full size adults in the back and your 2" drop is gone.
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Master Blaster
Dec 4, 2011
Ottawa, ON
On my computer now. Here's that video by ChrisFix:


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