03 sierra blower fan problem

Discussion in 'General Chevy & GM Tech Questions' started by dwmski, Jul 21, 2013.

  1. dwmski

    dwmski New Member

    An 03 4.8L sierra LE,, I recently had the electrical wiring plug to the TPS (throttle positioning sensor) replaced at GMC,, fixed that problem, but since then my interior AVAC (I think) system will only blow air straight out of the vents, the air speed control knob is working but cannot switch from straight out to floor air, to defrost floor, or defrost, etc.. the air will kick on when on defrost but the air is not directed in any other direction than straight out and not on the windshield...could the new wiring connector be causing this or is it a vacuum line thing or the directional switch itself,,, Thanks for any input...
  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    remove the negative battery connection then turn ignition to on this will drain/reset the HVAC controller computer. this should work.

    these systems are motor controlled by 5 volt power from the HVAC controller.
  3. dwmski

    dwmski New Member

    J cat, did you receive my response just prior to this, I checked my inbox and it was not in sent file,, I tried your suggestion and it did not work.. prior email contained addition info which may or may not help... thanks,,, dwmski (Dave)

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