Fitted new LED headlight bulbs? Here is how to check the dipped-beam pattern against a wall so you can spot a bulb that's incorrectly seated or a headlamp that needs adjustment.

Inch Autos headlight beam alignment guide for Irish roads with wall test, target downward aim and examples of high and low beam

How to check headlight alignment at home

  1. Prepare the car: Park on flat, level ground facing a straight wall or garage door. Check tyre pressures, remove unusual loads and follow your vehicle's normal-load instructions.
  2. Set the levelling dial: If your car has manual headlamp height adjustment, use the normal unloaded setting (often 0). Consult the vehicle handbook.
  3. Position the car: Measure 5 metres from the headlamps to the wall. Keep the vehicle straight and perpendicular to the wall.
  4. Mark the reference: Measure the height of each dipped-beam headlamp centre from the ground and mark that height on the wall, plus each headlamp centreline.
  5. Calculate the target: Find the manufacturer's specified downward aim, often marked on the headlamp housing. As an example only, a 1.0% downward aim means the flat section of the beam cutoff should be 5 cm below the headlamp-centre line at 5 metres. Other vehicles may need different settings.
  6. Check each lamp separately: Turn on dipped beam, cover one headlamp without overheating it, then observe the other lamp's clear cutoff. Repeat for the second headlamp.
  7. Inspect the beam shape: For suitable left-traffic dipped-beam headlamps, the pattern typically stays flat towards the right (oncoming traffic side) and rises towards the left. Aim the flat cutoff to your vehicle's specified target. Do not use the raised portion as the height reference.
  8. Adjust carefully: If the bulb is not fully seated, turn off the lights, allow the assembly to cool and refit the bulb correctly. Adjust the headlamp's proper vertical and horizontal adjusters only in accordance with the vehicle instructions. Do not force or arbitrarily rotate an LED bulb to compensate for an incorrect reflector pattern.

What does a correct beam look like?

Correct: A defined cutoff, controlled light on the road, and no excessive light above the cutoff on the oncoming-traffic side.

Too high: The cutoff is above the manufacturer's target. This can dazzle approaching drivers.

Too low: The cutoff is well below the target, reducing usable visibility ahead.

Still not getting a clean beam pattern?

Check that the correct bulb and fitting have been supplied for your exact vehicle and headlight type (halogen, xenon or factory LED), that any required retaining holder is fitted correctly, and that the headlamp lens and reflector are in good condition. LED replacement bulbs are not suitable for every headlamp design.

Need help? Send Inch Autos your vehicle make, model, year, headlamp type and a clear photo of the dipped-beam pattern on a wall. Contact Inch Autos.

Important: This wall test is an approximate check, not a substitute for a calibrated beam setter. Headlamp aim, beam pattern and bulb legality must meet applicable Irish requirements. An acceptable wall pattern alone does not establish NCT compliance or legal approval of an LED conversion.