Condensation on inside of headlamp - we dont want that, but it is inevtiable that humid weather (humidity greater than 90% and temperature changes will make fog patches. Countless hours has been spent to seal with silicone, headlamp assembly is waterproof in normal rain and is not affected even if driving 80miles/hours. During prolonged 90-100% humid weather and temperature changes, fog patches on inside of front lens will appear. Typical triggers are downpours, days of misty rain, fog and of course car washes. Steam under pressure easily enters the rear vents and creates fog patches. Silicone seals are soft and can be damaged if direct high pressure guns are directed at headlamps. Fog patches will dry out within a day or two with humidity levels under 50%. Parking car in the sun letting the sun heating up headlamps will dry them up quicker. In Toronto, with average humidty levels of about 55%, fog patches have been a rarity. I have been using high pressure water guns on a bi-weekly basis on my SHO, as long as I dont spray directly on headlight, minimal fogging happens. The Hella units have small white vents that I have blocked off with a piece of rubber, thinking the assemblys venting system was good enough. Taking those plack pieces out may increase circulation, but it will also introduce more dirt inside optical reflector and lenses.
Above: These holes will vent air from inside the Hella unit to the headlight box.
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