GMC Safari

I recently had my Safari in Pep Boys to have the alternator replaced. After picking it up and starting it I noticed the AC was not coming out of any of the top vents. Air was only coming out of the defrost and passenger floor area. I know this was working properly prior to Pep Boys working on the alternator. Could they have knocked a vacuum line or electrical connection loose. They were not able to look at it at time. I must bring it back they told me. I was hoping it was something simple I could fix myself.
July 28, 2007.

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