Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to all models, 2000 - 2019.

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  All All 2000 - 2019

• The customer may comment that the A/C blows warm or performs poorly.

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  Customer may comment that there A/C blows warm or they have poor A/C performance.

Steps to confirm (in the document’s order)

1. Record the A/C high and low pressures, the high side sensor reading, the A/C compressor duty cycle and, if equipped, the refrigerant solenoid valve command in HVAC data.

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   * A/C High and Low pressures * High side sensor reading * A/C compressor duty cycle * Refrigerant solenoid valve command in HVAC data (if equipped)

2. Record the outside temperature, the humidity and the vent temperature.

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   * Outside temperature * Humidity * Vent temperature

3. With an automatic HVAC system, read the inside, outside and duct temperature sensors, and the evaporator temperature sensor if equipped, from HVAC data with the scan tool.

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   If the unit is equipped with an Automatic HVAC system, go into the HVAC data with the scan tool and get the following readings: * Inside temperature sensor reading * Outside temperature sensor reading * Duct temperature sensor readings * Evaporator temperature sensor reading (if equipped)