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NO AC and all temps read negative 39 or 40 degrees

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Dealership says compressor is bad and wants 1400$ to replace it. Snapon scan tool says all HVAC readings are negative 39 or negative 40 degrees. 


I suspect there is an HVAC control module that needs replaced but need help diagnosing. 

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Windshield temp says 32 degrees when it's 85 outside. Shows interior duct temperatures of -40 degrees. It gets cool in the truck but not cold. Heat works fantastic. It's dual zone the.p if it matters. 


Head pressure looks to be correct. Line going into firewall is cold and dripping. Compressor kicks on just fine. 

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Sound's like a sensor problem, may have to purchase a detailed schematic of the auto-air system to see how many sensors there are and locate them and test them individually.

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