The A/C compressor on my 2010 2500 HD will only run in defrost when the temp is above about 40 deg. I'll be driving after pulling it out of the garage and all of a sudden the windows fog completely over and I can see nothing. Rolling down the windows and putting the fan on high with the temp full hot SLOWLY begins to defrost a small spot enough to drive. I know it's the compressor shutting off, but the dealer says this is normal. Compressor should not run below freezing, but that's when I need the defroster! Another truck exactly like mine runs the compressor regardless of outside temp. Any suggestions? Last winter I read a "low pressure switch closed" code.

 

do you have a build code c42, c67 or cj3? check the glove box build sheet. There is a module reprogram to address this if you have one of those build codes.

 

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> meternerd,

I’m sorry you are experiencing this issue with your vehicle. Would you please PM me your VIN, so I can look into this further?

Louis
GM Customer Service