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I've always felt that my 2014 Lexus IS350 F-Sport does a poor job of illuminating the road ahead but ignored it assuming that it was more due to the car's low ride height than anything else.

However, in a parking lot today I had the opportunity to see the overall beam pattern on a wall with horizontal lines for reference. This is with the car about 4-5 m away from the wall, parked on a level, horizontal ground.

Lexus IS350 F-Sport headlight pattern

The picture shows the left side beam is pointed slightly lower than the right side. The difference in height is roughly 15 cm (6 in).

I know that it's normal for car headlights to have a diagonal pattern to them to avoid dazzling oncoming traffic, and these are visible in the photo as well.

But is it normal for one headlight to point lower than the other?

This is a LHD vehicle (we drive on the right side of the road, like the US).

An additional datum point

My friend has a 2015 IS350. This is what his car's beam pattern looks like with the car in the same parking spot.

Friend's 2015 Lexus IS350

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    beam pattern looks almost identical to me - both pictures have two peaks - the first picture has both peaks slightly higher than the ones on the lower picture.
    – Mauro
    Commented Dec 6, 2016 at 10:01
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    It may be intentional, so as not to blind oncoming traffic on the left, but to illuminate the right side a little better. I would leave it.
    – cory
    Commented Dec 6, 2016 at 14:40
  • @cory I thought that not blinding oncoming traffic is taken care of by the slanted pattern of the individual beams. Plus it doesn't explain the level beams on my friend's IS350
    – Zaid
    Commented Dec 6, 2016 at 16:02

2 Answers 2

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I would say the two peaks should be at the same height. In the UK, beam alignment is part of the annual MOT roadworthyness test, and the government publish a guide as to how to set them up:

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/260552/headlamp-aim-guide.pdf

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/260553/headlamps-lets-aim-to-get-it-right-leaflet.pdf

Basically, park the car 2'/600mm from the wall, and adjust the lamps so the beams are the same height, and slightly below the centre-line of the lamps.

As you drive on the other side of the road, obviously you'll need to reverse the diagrams in the second link.

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  • The US standards have them at 2 at different heights and aimed at different angles. This is going to strongly depend on where you live. Need to use information from whatever department of transportation that your country may have.
    – Brian Knoblauch
    Commented Dec 6, 2016 at 17:14
  • @BrianKnoblauch I'd like to check out the US standards. Do you have any links?
    – Zaid
    Commented Dec 12, 2016 at 20:02
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It looks like this is a common issue with this IS generation. There are quite a few forum posts out in the wild on the topic, and on how to adjust it.

I decided to follow the recommendation in Nick C's post and am pleased with the results:

Post-adjustment beam pattern

Instructions to adjust the headlight beam

Tools Required

  • 8 mm close-ended wrench/spanner (preferably a ratcheting one)
  • Patience
  • Dexterity

Steps

  1. Pop open the hood/engine bonnet

  2. At the base of the back of the headlight there is a white hex nut towards the bottom. Use the wrench/spanner to twist this adjustment nut. I found that rotating the nut anti-clockwise raised the beam level.

    White hex nut

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