heater/ac switch will not run on 1,2 or 3?

2004 CHEVROLET SILVERADO
173,000 MILES • 4.3L • V6 • 2WD • AUTOMATIC
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RAHLO18
  • MEMBER
  • 1 POST
The control switch only runs on 4 & 5. Will not run on 1,2 or 3?
Sep 2, 2015 at 5:18 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.
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Most likely a bad blower motor resister. Check that first. Here is the location you should look for burn mark or signs of overheating on the resistor. If the resistor is okay I would replace the switch. Check out the images (below). Please let us know what happens.

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Sep 2, 2015 at 7:20 PM
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