Condensation on the interior surface of a headlight is indicative of a seal leak or crack in the headlight housing. Cracks can result from incorrect installation, impact damage, heat, extreme cold, or manufacturer defects. Repair of cracks and leaks generally requires removal of the headlight from the vehicle to identify and repair the location of the leak. If possible, you should dry the headlight's interior surface to ensure condensation doesn't create further damage or degrade the visibility of the headlight system.
Remove the headlight from the body of the vehicle. Usually, the headlight is held in place with two to four bolts or screws. Many vehicles, such as those from Dodge, require torx-head screwdrivers for removal. While most headlights can be visually inspected to identify the location of the bolts or screws securing the housing to the vehicle, it may be necessary to consult an online resource, mechanic or automotive handbook.
Remove the bulb from the housing. Most headlight designs secure the bulb to the housing with a gasket and pressure. Turn the headlight bulb counterclockwise and pull away from the housing to remove.
Dry the inside of the headlight housing. If access is limited, use a hair dryer to blow warm air into the housing to remove any condensation.
Identify the source of the leak. If the leak is the result of incorrect seating of the headlight into the headlight housing, spray the gasket with silicone spray and replace the bulb properly.
Repair any cracks or gaps with plastic epoxy. Mix the epoxy according to manufacturer instructions. Apply the epoxy to the inside of the headlight, if possible. Spread the epoxy on the crack and extend it beyond the edges to ensure a good seal. Apply epoxy to the outside of the headlight at the point of the leak to ensure a solid seal. Allow the epoxy to fully cure.
Reinstall the headlight bulb. Reinstall the headlight.
