Front And Rear Lamp Condensation
Some customers may complain of condensation/misting/fogging inside the exterior lamps. Condensation/misting/fogging is a natural phenomenon which can occur under wet and/or humid atmospheric conditions. It is triggered by temperature differences between the inside and outside of the lamp unit. Exterior lights have vents and are not completely closed to the environment, therefore replacing the light unit will not correct this symptom. With the introduction of clear plastic lenses, condensation is likely to be more noticeable but does not affect the performance of the lamp. Condensation will clear with regular use of the lights under warmer and drier atmospheric conditions
A lamp that exhibits condensation should be evaluated under warm (20°C ± 5°C) and dry conditions (50% RH ± 5% RH) with all functions operating for a minimum of 60 minutes. If the condensation improves (i.e.: it starts to clear, but has not necessarily completely cleared) during this time, it indicates that the lamp is functioning as normal. This means the lamp integrity has NOT been breached and the condensation will clear given sufficient time, consequently the lamp must NOT be replaced
- Where appropriate, make sure that bulb covers are correctly installed and make sure that all breathers (tubes or membrane patches) are free from dirt/debris and fitted correctly (contamination or poor fitting can all contribute to the formation of condensation). If any of these are determined to be the cause of the condensation, measures should be taken to dry out the lamps and to make sure that the bulb covers/breathers are installed correctly
- Make sure that a Jaguar Land Rover approved battery support unit is connected to the vehicle throughout the lamp evaluation procedure
- The owner's handbook clearly states that condensation may form on the inside of lamp lenses and is caused by atmospheric conditions. It explains that it is not detrimental to lamp performance and will clear during normal usage
- Pools of water and high levels of condensation would indicate that the lamps' sealing has been compromised. Check for damage and inspect the condition of caps and breathers
- Differing layout on the opposing sides of the vehicle can lead to different levels of condensation inside the lamps from side to side. As a result of this, the rate at which condensation clears may also differ from side to side
- This information bulletin contains examples of normal condensation generated from atmospheric conditions. A thin mist can form on the interior of clear plastic lenses, this is not detrimental to the lamp's performance. This thin mist will eventually clear through normal use, exiting through the lamp's venting system
- Photographic evidence of the condensation levels prior to and after drying time should be provided with every warranty claim (see guidance above regarding how the lamps should be allowed a minimum period of 60 minutes with all functions operating to encourage the condensation to clear). Failure to do so may result in the claim being rejected
Condensation or moisture can be more noticeable during the months of spring and autumn when there is a likelihood of a higher moisture content in the air. It can occur when there is a temperature difference on either side of the lens surface. This can often be seen in the evening and morning sunshine or when cold water makes contact with a warm lamp lens. When a lamp is warmed unevenly by the sunshine, the surface area in direct sunlight will be approximately 10°C higher than the remainder of the lamp. When warm air circulates within the lamp and makes contact with the colder surfaces, moisture can appear on the lens as water condenses out of the warmer air. Condensation may occur when washing a vehicle with cold water on a warm day or when the lamps are warm and vice versa. This is the same phenomena as with the formation of dew on the surface of a glass window pane
LED lamps project less heat towards the clear lens and therefore condensation can occur and can take longer to clear than in other types of lamps
The following process describes the formation and clearance of condensation:
- Air and moisture enter the device through the ventilation when the vehicle is OFF
- The temperature of the lens surface falls below the dew point, due to driving/rain/washing or daily temperature variations
- Condensation is formed on the cold lens surface
- The temperature of the cold surface rises again due to sunshine and/or lamp operation and the moisture inside the lamp is removed through the ventilation, the condensation will clear
- Time to clear depends on the lamp design, environmental conditions and the amount of condensation formed
Shown below are examples of normal exterior lamp condensation. This would NOT be covered by warranty and the lamp(s) must not be replaced
Shown below is an example of abnormal exterior lamp condensation that may be covered by warranty. Warranty may be accepted providing the lamp does not exhibit any visible signs of external damage.
In the photograph shown below, note the drip marks or streaks in the condensation and the standing water within the lamp, this is not acceptable and clearly shows a water ingress related fault with the lamp