Lamp Lens Defogging (Front/Rear)
The images below are not specific to vehicle and are used only as examples between lamps with and without condensation issues.
FRONT LAMP
Occasionally, a light layer of condensation may accumulate on the inside lens of the front or rear (tail) lamp assemblies. This condition may happen after the specific lamp system has been activated, brought up to operating temperature, deactivated, and then rapidly cooled (such as a cold rain or a vehicle wash). Condensation on the inside lens may also occur under certain atmospheric conditions, such as when a vehicle has been stored outside, overnight (i.e., a warm humid day, followed by clear, cool night). This condition may change as the atmospheric conditions change, allowing the condensation to evaporate. Although, activating the affected lamp system continuously, may help accelerate the evaporation process.
| Condensation starting to evaporate. Normal Operation. |
A lamp lens exhibiting a condensation/fogging condition should be evaluated in an interior service bay environment. Make sure the outside lens surface is completely dry and note the amount of condensation present on the inside lens. Operate the affected lamp system for 20 minutes. After 20 minutes, check if the condensation has started to evaporate. Less condensation indicates the lamp sealing has not been breached, and that the lamp does not need to be replaced.
| Example of a breached lens seal with condensation that is not evaporating after 20 minutes. |
Condensation that does not start to evaporate after 20 minutes of system operation may indicate an issue with the lamp weather seal. If the affected lamp has large amounts of water droplets, visible on most internal surfaces, or if the customer states the condensation on the lamp lens is always present and does not dissipate, the affected lamp should be replaced.
REAR LAMP
The images below are not specific to vehicle and are used only as examples between lamps with and without condensation issues.
Some customers may report that on occasion, vehicle exterior tail 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 vehicle 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 tail lamps on will usually accelerate this process.
| Condensation starting to evaporate. Normal Operation. |
A tail lamp that exhibits condensation/fogging should be evaluated in a service bay environment by first drying all water from the outside surface of the lens and operating the lamp for 60 minutes by turning on the vehicle lights and turn on the hazard lights. If the condensation/fogging has begun to clear from the tail lamp lens within 60 minutes with the tail lamps operating, this indicates the tail lamp sealing has not been breached, and the tail lamp does not need to be replaced. The tail lamp should be checked every 15 minutes.
| Example of a breached lens seal with condensation that is not evaporating after 20 minutes. |
If the condensation/fogging has not begun to clear after 60 minutes with the tail lamps operating, or the lamp has large amounts of water droplets visible on most internal surfaces, this indicates a problem with the tail lamp sealing that has allowed water to enter the tail lamp. In this instance, the customer is also likely to report that moisture in the tail lamp is always present and never disappears. A tail lamp that exhibits internal moisture permanently should be replaced.