Lighting - Ext. Lamp Condensation/Replacement Guideline
Bulletin No.: IB07-11-S013Issue Date: November 2007
Exterior Lamp Condensation And Replacement Guidelines
(This Bulletin Supercedes IB05-11-S004)
Affected Vehicles:
2003-2008 Isuzu Ascender
2007-2008 Isuzu i-290/i-370 (TI)
2006 Isuzu i-280/i350 (TI)
Service Information
This bulletin is being revised to update models and model years.
The following information is being provided to better define the causes of condensation in exterior lamps and includes guidelines for determining the difference between a lamp with a normal atmospheric condition (condensation) and a lamp with a water leak.
Some exterior lamps such as cornering turn signal backup headlamps or tail lamps may exhibit very small droplets of water a fine mist or white fog (condensation) on the inside of the lamp lens. This may be more noticeable on lamps with "multi-lens" designs and may be normal during certain weather conditions.
Condensation occurs when the air inside the lamp assembly through atmospheric changes reaches the "dew point". When this takes place the moisture in the air within the lamp assembly condenses creating a fine mist or white fog on the inside surface of the lamp lens.
Most exterior lamps on General Motors vehicles use a vented design and feature a replaceable bulb assembly. They are designed to remove any accumulated moisture vapor by expelling it through a vent system. The vent system operates at all time; however it is most effective when the lamps are ON or when the vehicle is in motion. Depending on the size shape and location of the lamp on the vehicle and the atmospheric conditions occurring the amount of time required to clear the lamp may vary from 2 to 6 hours.
Condensation
Condensation can cause a fine mist or white fog on the inside surface of the lamp lens and is more likely to occur after a period of high humidity.
^ May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface.
^ The condition should clear of moisture when the vehicle is parked in a dry environment or when the vehicle is driven with the lights ON.
^ A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance.
If the above conditions are noted the customer should be advised that replacement of a lamp assembly may not correct this condition.
Water Leak
Numerous and various size drops of water collecting on the inside surface of the lamp lens after the vehicle has been exposed to rain or a car washing environment.
^ A condition that covers more than half the surface of the lamp lens.
^ An accumulation of water in the bottom of the lamp assembly.
^ A condition that won't clear when the vehicle is parked in a dry environment or when the vehicle is driven with the lights on.
^ A comparison of the equivalent lamp on the opposing side of the vehicle indicates a different performance.
Any of the above conditions would indicate the need to service the lamp assembly.
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