Manufacturer communication — 2006 GMC YUKON DENALI XL

• 2020 and prior GM passenger cars and trucks.

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  2020 and Prior GM Passenger Cars and Trucks

• Exterior lamps such as cornering, turn signal, backup, head or tail lamps may show very small water droplets, a fine mist or white fog (condensation) on the inside of the lens.

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  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.

Possible causes

• Most exterior lamps use a vented design and expel accumulated moisture vapor through a vent system.

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  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 is most effective when the lamps are ON and the vehicle is in motion.

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  The vent system operates at all times, however, it is most effective when the lamps are ON and when the vehicle is in motion.

Steps to confirm (in the document’s order)

1. Normal condensation may sit mainly in the lens corners (near the vents) and should not cover more than half the lens surface.

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   May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface.

2. Normal condensation clears when the vehicle is parked in a dry environment or driven with the lights ON.

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   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.

3. With normal condensation, the equivalent lamp on the opposite side of the vehicle behaves similarly.

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   A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance.

4. A water leak shows numerous drops of various sizes on the inside of the lens after rain or a car wash.

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   Numerous & 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

5. An accumulation of water in the bottom of the lamp assembly indicates the lens or lamp assembly needs service.

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   An accumulation of water in the bottom of the lamp assembly.

Repair

• If a lamp is found to leak, review the most recent version of Service Bulletin 02-08-42-001 on inspecting for impact damage and modification.

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  If a lamp is found to be exhibiting a leak, review the most recent version of Service Bulletin 02-08-42-001 for information regarding impact damage and modification inspection.

Caution

• If those conditions are noted, advise the customer that replacing the lamp assembly may not correct the condition.

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  If the above conditions are noted, the customer should be advised that replacement of a lamp assembly may not correct this condition.

• Moisture that comes and goes is considered a normal condition.

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  Moisture “coming and going” is considered a normal condition.