Question about 2004 GMC Sierra

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I have a 2004 GMC duramax. I recently had to change both my batteries and after doing so my a/c and heater will only blow air through the windshield vents. When I select a/c it dose blow cold air but when I select it to vent through the dash vents or onto the floor it only continues to blow onto the windshield. Same with the heat. I don't know if this could possibly have anything to do with changing the batteries but it's for sure I didn't have this problem until the Batteries were r&r. Appreciate any help...Rick

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I believe there is a small motor with 2 springs in the below dash duct work, it may be right above the gas pedal (but I am not 100 % sure) it
contols where the air flows in the ducts. Some what of a damper affair. I have the same problem in my 95 Tahoe, it just seems to stick and often lets go after a few minutes. You may need to give it a little persuasion, but do it carefully because you may drop the two springs off and it may mean pulling the dash out. Lay on you back and locate the motoer and get a helper to move the setting from dash to foor to vent , but give about 45 seconds between each move give a little pull. WD 40 may help but just a liittle.

hope this may help Ron

Posted on Aug 06, 2010


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