1997 GMC Sonoma fan motor

1997 GMC SONOMA
160,000 MILES • 4 CYL • 2WD • MANUAL
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JOEDB
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My '97 GMC Sonoma blows cold air, but, it only blows through the floor and dash outlets as if it was set on defrost. The fan will blow at all speed settings but will not blow through the dash air vents no matter what you set it on, (A/C, max A/C, fan, defrost, or defrost/heat) I've checked 3 of the 5 vacuum hoses and they appear to be fine. The other 2 and I have not been able to locate. I have found no blown fuses or relays. Please advise what this could be and how to fix.
Jul 5, 2010 at 7:39 PM
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RICHZOMBIE
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the blend door may be stuck / bad and not allowing air to change flow to get to other vents. only way to check is to go into dash and inspect the blend doors and other HVAC components.
Jul 5, 2010 at 7:42 PM
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JOEDB
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i recently bought the truck and when i test drove the truck the air vents worked, BUT, the previous owner did leave the hood unlatched and it flipped up and DESTROYED the windshield( I got a new windshield out of the deal), could it be possible that some small pieces of glass could be trapped in there causing the problem.
Jul 5, 2010 at 8:01 PM
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RICHZOMBIE
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if they worked when you test drove it then that probably is not it
Jul 5, 2010 at 8:18 PM
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JOEDB
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The test drive took place before the windshield was busted. I told him I would possibly buy the truck, then he had the mishap. So he replaced the windshield before I bought the truck.
Jul 5, 2010 at 8:24 PM
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RICHZOMBIE
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oh ok, then yes that would definitely seem like a piece of the puzzle. i'm sure there are pieces of glass either in the cowl area (outside of car, below bottom of windshield) or some may have even fallen into the defrost vents.
Jul 5, 2010 at 8:33 PM
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JOEDB
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Why thank you Mr Zombie. I will look into that the next chance I get. Hopfully I can get to the problem without getting too far into the dash removal process. You think my shop vac will get the job done?
Jul 5, 2010 at 8:50 PM
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RICHZOMBIE
  • ✓ASE Certified Mechanic
  • 173 POSTS
  • ASE Certified Mechanic
i'd say that would definitely help a lot at the very least, they are pretty powerful.
Jul 5, 2010 at 9:00 PM
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