DATE: September 27, 2006
Exterior Lamp – Lens Fogging
Some customers may report that on occasion, vehicle exterior lamp assemblies are fogged
with a light layer of condensation on the inside of the lenses. This may be reported after
the lamps have been turned on and brought up to operating temperature, turned off, and
then rapidly cooled by cold water (such as rain, or the water from a car wash). Lens
fogging can also occur under certain atmospheric conditions after a vehicle has been
parked outside overnight (i.e., a warm humid day followed by clear cool night). This will
usually clear as atmospheric conditions change to allow the condensation to change back
into a vapor. Turning the lamps on will usually accelerate this process.
A lamp that has large amounts of water droplets visible on most internal surfaces indicates
a problem with the lamp sealing that has allowed water to enter the lamp. In this instance,
the customer is likely to report that moisture in the lamp is always present and never
disappears. A lamp that exhibits internal moisture permanently should be replaced.