Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to 2019 and prior GM passenger cars and trucks.

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  2019 and Prior GM Passenger Cars and Trucks

• Exterior lamps such as cornering, turn signal, backup, headlamps or tail lamps may show very small droplets of water, 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

• The moisture in the air inside the lamp assembly condenses, creating a fine mist or white fog on the inside surface of the lens.

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  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.

• The vent system operates at all times but 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 should clear 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. A condition that covers more than half the surface of the lamp lens indicates the need to service the lens or lamp assembly.

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   Note: Any of the conditions listed below would indicate the need to service the lens or lamp assembly. • A condition that covers more than half the surface of the lamp lens.

4. An accumulation of water in the bottom of the lamp assembly indicates the need for service.

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

5. A condition that will not clear when the vehicle is parked in a dry environment or driven with the lights ON indicates the need for service.

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   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.

6. The most reliable way to identify a non OE lamp is to compare it with the replacement service part or a like vehicle.

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   The most reliable way to identify a non OE part is to compare it to the replacement service part or a like vehicle.

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.

• Different performance of the lamps on opposite sides of the vehicle does not always indicate that one lamp is bad and the other normal.

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  Note: A different performance of lamps on opposite sides of a vehicle DOES NOT always indicate that one lamp is bad, and the other is normal.