Headlamp Fogging
| Subject: | Headlamp Fogging |
| Models: | 2007 Caprice, Lumina (Export) |
PIRs have been received which mention headlamps with fogging or water intrusion. In diagnosing the cause of fogging, it is important that technicians understand the following:
| • | The vented lamp design |
| • | How to clear minor fogging |
| • | Criteria for headlamp replacement due to water intrusion |
Vented Headlamp Design
Vented lamps with clear lenses (no optics) are prone to showing signs of any moisture present within the lamp.
The design of vented lamps can result in the formation of minor condensation (fogging) on the inside surface of the lens under certain operational and climatic conditions.
For example, in humid weather, when vehicles are parked and headlamps turned off after prolonged usage, moisture-laden air is drawn into the lamp via its vent system and condenses on the lens as it cools down. This minor condensation (fogging) will usually disperse after 3-4 minutes driving with the headlamps on.
If an owner comments of condensation in headlamps, the first thing to do is determine if there are signs of normal fogging, or if the lamp has water intrusion due to leakage.
Minor Condesation/Fogging
This will be in the form of a mist on the interior surface of the lens. This needs no dealership action, as the fogging will disperse during the time the vehicle is left standing or after 3-4 minutes driving with the headlamps on.
Service advisors should be alert customers to this headlamp characteristic in order to avoid future comments of minor fogging.
Water Intrusion
A headlamp lens with severe fogging and with water droplets or a visible amount of water in the bottom of the headlamp must be investigated to determine the cause of water intrusion.
Possible causes of water intrusion are as follows:
| • | Vent tubes, dust caps and/or dust cap seals missing, or incorrectly installed. |
| • | Turn signal and/or electrical connector is incorrectly installed. |
| • | Lens housing seal leak. (This is unlikely as the headlamp supplier pressure tests every production headlamp). If this is confirmed, the lamp will require replacement. |
Important:
• Where water has leaked in via connector, caps, etc, that have been re-installed, it may be necessary to leave the headlamps on for up to 30 minutes to clear the remaining condensation. • If a lamp is replaced for water intrusion, a clear description of diagnosis and approximate amount of water intrusion should be noted on the repair order.
Engine Bay Cleaning Precaution
High pressure water should not be directed at the rear of the lamp as this can lead to water intrusion through the lamp’s vent system.
