The seal around headlights tend to break down over time leaving gaps around the headlight. Which can let water, bugs & moisture to enter. If the condensation & moisture in the headlight housing builds up to a dangerous level it can cause a electric fault & effect the headlight control modules.
The seal around headlight units may become loose or leave a gap in any year & model of car or van. Modern cars have this problem as new headlamps are not sealed air tight unlike older vehicles. As more moisture starts to build up it will effect the light output & does certainly make the car look terrible.
Note - Headlight resealing is suspended until further notice.
For now please try these simple steps.
Check the headlight air vents are not blocked by dust or leaves as the moisture needs to escape. A quick blow with a air compressor should unblock the air vents.
Remove back cover of the headlight for 2 hours that should clear up any moisture in the headlight. Be sure to put it back once the headlamps are dry.
Inspect the outer headlight lens for cracks or small holes.
If you have replaced your headlight bulbs recently. Have you closed the back headlight cover tight?
If your car is quite new be sure to contact it`s manufacturer. Check warranty
Headlight seals which surrounds the headlamp housing may have broken away or come apart or the air vents could be blocked.
Best way is to reseal the headlights to stop the moisture getting any worse.
Yes it can cause electric shorts & maybe blow a fuse or two.
Yes if it distorts the beam pattern of the light output.
A single drop of water can shatter a hot bulb. Condensation will cause corrosion of the terminals in the connector.
Maybe a design fault please ask your car dealership for further information.
Please check your headlight housing for any openings & holes. You may use a mini vacuum (on low power) to suck any insects out from the headlight.
Bad seals or blocked air vents, Headlights need to breathe and any moisture needs to escape through the vents.
Please do not drill directly into the headlight lens, If you must drill a few holes in the back headlight cover for further airflow.