2004 Chevy Silverado Selector control won't change from def

2004 CHEVROLET SILVERADO
103,000 MILES • V8 • 2WD • AUTOMATIC
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TLECSTR
  • MEMBER
  • 1 POST
When I turn the knob from defrost to feet and then to face, it won't change . It always stays blowing through the deforst vents. I have tried it on heat as well as A/C.
Also, the fan speed sometimes changes form fast to slow and then back.
Feb 24, 2009 at 1:30 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,246 POSTS
Hi:
The vents are run by vacuum. Check under the dash to see if there are damaged or disconnected lines. Also, listen for a hissing sound that may indicate a leak.

Let me know what you find.

Joe
Feb 24, 2009 at 11:56 PM
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