Misted headlights and headlight aiming

Headlight aiming

The headlights are aimed before the car is delivered. If you often carry heavy loads, they may need re-aiming. Manufacturers recommend that an authorised dealer or service centre does the adjustment.

Lamp misting

Headlights, rear lamps and the indicators in the mirrors can mist up after heavy rain or washing. This is similar to the condensation that forms on a side window in the rain — it does not mean anything is wrong with your car.

Why it happens

A lamp is a relatively closed, confined space. When it is switched on the temperature inside rises sharply (the housing and reflector can even deform), so the heat has to be carried away. The housing has openings that allow convection to remove it — the larger the temperature difference, the more active the convection. During convection, moisture from the air inevitably gets into the lamp. Sunlight, convection and heating of the bulb mean that at low temperatures the moisture condenses easily on the lamp's surface as mist or droplets. That is misting.

What to do

• If moisture appears inside a headlight or a mirror indicator, the cause may be high humidity or a large temperature difference between the car and the surroundings. Switch the headlights or indicator on while driving — after a while the moisture will evaporate.
• If a noticeable amount of water stays inside the headlight, take the car to an authorised dealer or service centre.