New member here and have one that scratches my head...I have a 94 stepside chevy truck, 5.7ltr. auto, 2w drive. I'm stumped on the fact that when I turn on my defroster, my ac, (compressor), kicks on.

Any advice out there ?

 

That's normal the AC compressor is drying out the air. It's not a problem, if it didn't you would have more condensation on your windows.

Oh and welcome aboard.

 

Welcome to the Truckforums!
This isn't a tech section. perhaps you'll get a better answer in the silverado section.