my ac/heater will only blow on the highest setting. Level 5. How can I repair it

2004 CHEVROLET AVALANCHE
160,000 MILES
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SMITTYSFATHER
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this problem began approx. A week ago.
Oct 18, 2011 at 12:53 PM
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JDL
  • CAR REPAIR CONTRIBUTOR
  • 16,098 POSTS
With automatic hvac check for applicable trouble codes. If the hvac module detects a problem, it will default to defrost. Some of the national brand autostores used to check some codes for free. I haven't looked at your wiring, yet.
Oct 18, 2011 at 2:09 PM
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JDL
  • CAR REPAIR CONTRIBUTOR
  • 16,098 POSTS
I did find a TSB possibility. The hvac control harness may rub against a sharp edge of instrument cluster brace, causing the actuator control to short.
Oct 18, 2011 at 2:16 PM