my heat blows cold unless i have defrost on then it blows warm

2001 PONTIAC MONTANA
150,000 MILES
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JBASEY
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  • 5 POSTS
when i turn on my heat it comes out cold but when i turn on defrost it blows warm
Nov 7, 2011 at 10:46 PM
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RIVERMIKERAT
  • CAR REPAIR CONTRIBUTOR
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Check the vacuum and electrical lines to the air doors. One is most likely loose or missing.
Nov 7, 2011 at 10:49 PM
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JBASEY
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  • 5 POSTS
where are the vacuum air doors
Nov 7, 2011 at 10:52 PM
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JBASEY
  • MEMBER
  • 5 POSTS
thankyou for the response where are the electrical lines and vacuum air doors located
Nov 7, 2011 at 11:16 PM
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RIVERMIKERAT
  • CAR REPAIR CONTRIBUTOR
  • 6,110 POSTS
The AC/heater blower assembly is located under the dashboard, and behind the glovebox. Take a look at the pictures.
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Nov 7, 2011 at 11:19 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.