Thread: hvac door #3
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Old 11-03-2009, 04:17 AM   #10 (permalink)
sag2
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Join Date: Nov 2002
Location: San Francisco Bay Area
Posts: 2,012
The HVAC control head "learns and knows" the door position by driving it until the motor stalls in both directions. It then knows the limits, and since it is a stepper motor it then counts the number of steps between the stalled positions, and can position the door anywhere in between, or at the stalled positions.
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Fixing them most of the time and loving it.


06 4x4 short Laramie auto 12/30/05
04 HO 4x4 Short Laramie 12/31/03.
03 2500, CTD, short box, 4x4, Silver Laramie Sport 12/13/02
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